Metal detection device and methods of operation thereof

ABSTRACT

Disclosed are methods and devices for detecting retained surgical items or other objects having a magnetic signature within a corpus of a patient. The device can comprise a handle, a shaft extending from the handle, and a distal sensing portion positioned distally of the shaft. The distal sensing portion can comprise one or more gradiometers comprising a plurality of magnetometers. The device can further comprise one or more output components configured to generate a user output to alert a user of a detected object.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/649,779 filed on Feb. 2, 2022, which is a continuation of U.S. patentapplication Ser. No. 16/950,119 filed on Nov. 17, 2020 (now U.S. Pat.No. 11,272,857 issued Mar. 15, 2022), which is a continuation of U.S.patent application Ser. No. 16/983,793 filed on Aug. 3, 2020 (now U.S.Pat. No. 10,881,323 issued Jan. 5, 2021), which is a continuation of PCTApplication No. PCT/US2020/044649 filed on Jul. 31, 2020, which claimsthe benefit of U.S. Provisional Application No. 62/900,385 filed on Sep.13, 2019 and U.S. Provisional Application No. 62/927,702 filed on Oct.30, 2019, the entireties of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to the field ofmagnetometer-based metal detection, and, more specifically, to animproved magnetometer-based metal detector for detecting retainedsurgical items such as sharps or RFID-tagged sponges, metallic implants,metallic wires, and other objects having a magnetic signature within acorpus of a patient.

BACKGROUND

Surgeons and other operating room (OR) professionals spend a significantamount of time and resources locating retained surgical items (RSIs)such as lost surgical needles, broken parts of surgical instruments, orother types of sharps in their patients. The growth of minimallyinvasive laparoscopic and robotic procedures have made it harder forsurgeons to find lost needles, broken instruments, and other types ofsharps and fragments. Retained objects can cause serious harm topatients including potential chronic pain or organ injury. As a result,surgeons and other OR professionals go to great lengths to ensure alltools and instruments are accounted for. However, when dealing with anaverage of 300 tools per surgery, multiple rotations of staff, and partsof instruments breaking off, searching for RSIs have become more common.According to one study, 63.8% of all surgeons surveyed experienced alost needle event during minimally invasive surgery within the last 12months. Moreover, 89.6% of surgeons surveyed reported one to five needleloss incidents during their careers. Furthermore, over 13% of eventsrequired more than 30 minutes to locate and recover the lost needle andin 3% of cases, surgeons were unable to recover such needles afterconducting a search. See Jayadevan, Rajiv et al. “A protocol to recoverneedles lost during minimally invasive surgery.” JSLS: Journal of theSociety of Laparoendoscopic Surgeons vol. 18,4 (2014).

Surgeons and other OR professionals often rely initially on a visualsearch for any metallic RSIs such as needles, sharps, and broken tools.If the item is not found, patients typically receive an X-ray scan andmore anesthesia as OR staff spend more time searching. This results ingreater exposure to radiation for patients and staff and an increasedrisk of complications from prolonged anesthesia time. When surgeonscannot ultimately locate the lost needle or sharp, patient disclosure isrequired and both hospitals and surgeons are at risk of reputationaldamage or litigation. In addition, RSI events are not reimbursable,leaving hospitals to absorb the costs of any further procedures orsettlements.

Traditional metal detection devices often lack the ability to determine,with high precision, the exact location of a metallic RSI within a bodyof a patient. Moreover, such devices are often not suitable for in vivodetection, not portable, and cannot be easily rotated to allow fornavigation through tortuous anatomy. Moreover, such traditional metaldetection devices cannot properly remove the effects of backgroundmagnetic field interferences or can only remove such interferencesthrough rudimentary single point measurements or subtraction algorithmsthat may result in inaccurate detection.

Therefore, a solution is needed which addresses the above shortcomingsand disadvantages. Such a solution should be portable and allow asurgeon to easily move and rotate the device within the body of apatient. Such a solution should also not be overly complicated and becost-effective and easy to manufacture.

SUMMARY

Disclosed are magnetometer-based metal detectors, metal detectionsystems, and methods of operation thereof for detecting metallic objects(e.g., RSIs, metallic implants, metallic wires, etc.) within a corpus ofa patient. In one aspect, a metal detection device is disclosedcomprising a handle, a shaft extending from the handle, and a distalsensing portion positioned distally of the shaft. The distal sensingportion can comprise a proximal gradiometer comprising a first proximalmagnetometer and a second proximal magnetometer, and a distalgradiometer comprising a first distal magnetometer and a second distalmagnetometer. The metal detection device can also comprise an outputcomponent configured to generate a user output to alert a user of adetected object and a microcontroller comprising one or more processorsand memory units. The one or more processors can be programmed toexecute instructions stored in the memory units to calculate adifferential signal from magnetic field measurements obtained from thefirst proximal magnetometer, the second proximal magnetometer, the firstdistal magnetometer, and the second distal magnetometer. The one or moreprocessors can be programmed to execute further instructions to apply atleast one of a signal filter and a derivative to the differential signalcalculated to obtain a detection signal.

The signal filter can comprise a high-pass filter and a low-pass filter(e.g., a second order or two-pole filter). For example, the high-passfilter can get rid of drift and offset and bring the average signal backto zero. The low-pass filter or second order filter (also known as atwo-pole filter) can more aggressively cut off high-frequency noise. Forexample, the high-pass filter can have a cutoff of 5.5 Hz and thelow-pass filter can have a cutoff of 10 Hz.

The one or more processors can be programmed to execute furtherinstructions to compare the detection signal against a threshold andinstruct the output component to generate the user output when thedetection signal exceeds the threshold.

Additionally, in another mode, the threshold can be removed or set belowzero in order to render it un-used for a given level or for a givenperiod of time or for a given product such that the sound or tone isalways on and the tone and or light can chance frequency and/orintensity as the signal grows and shrinks. This mode could allow forsignals below a threshold to be observed for response.

The first proximal magnetometer, the second proximal magnetometer, thefirst distal magnetometer, and the second distal magnetometer can betwo-axis magnetometers. The first proximal magnetometer, the secondproximal magnetometer, the first distal magnetometer, and the seconddistal magnetometer can each have an x-axis and a y-axis. The firstproximal magnetometer and the second proximal magnetometer can eachcomprise at least a +x-axis and a +y-axis. The +x-axis of the firstproximal magnetometer can be oriented opposite the +x-axis of the secondproximal magnetometer. The +y-axis of the first proximal magnetometercan be oriented opposite the +y-axis of the second proximalmagnetometer.

The first distal magnetometer and the second distal magnetometer caneach comprise at least a +x-axis and a +y-axis. The +x-axis of the firstdistal magnetometer can be oriented opposite the +x-axis of the seconddistal magnetometer. The +y-axis of the first distal magnetometer can beoriented opposite the +y-axis of the second distal magnetometer.

The second distal magnetometer and the first proximal magnetometer caneach comprise at least a +x-axis and a +y-axis. The +x-axis of thesecond distal magnetometer can be oriented opposite the +x-axis of thefirst proximal magnetometer. The +y-axis of the second distalmagnetometer can be oriented opposite the +y-axis of the first proximalmagnetometer.

In some variations, axes of the first proximal magnetometer and thesecond proximal magnetometer can be either aligned or orthogonal to axesof the first distal magnetometer and the second distal magnetometer.

Although reference is made to each of the magnetometers or magneticsensors comprising an x-axis (e.g., +x-axis) and a y-axis (e.g.,+y-axis), it is contemplated by this disclosure that any reference to ax-axis (e.g., +x-axis) or a y-axis (e.g., +y-axis) can also refer to asingle-axis magnetometer where the magnetometer or magnetic sensor onlyhas an x-axis or y-axis. Therefore, any references to four two-axismagnetometers can also be applied to eight one-axis magnetometers.

In other variations, at least one of the axes of the first proximalmagnetometer and the second proximal magnetometer can be not orthogonalto (or oriented at an oblique angle with respect to) at least one of theaxes of the first distal magnetometer and the second distalmagnetometer. For example, the distal sensing portion can comprise aproximal rigid printed circuit board (PCB), a distal rigid PCB, and adistal flexible circuit disposed in between the proximal rigid PCB andthe distal rigid PCB and connecting the proximal rigid PCB to the distalrigid PCB. The first proximal magnetometer and the second proximalmagnetometer can be coupled to the proximal rigid PCB. The first distalmagnetometer and the second distal magnetometer can be coupled to thedistal rigid PCB. The distal rigid PCB can be angularly rotated withrespect to the proximal rigid PCB about the distal flexible circuit by atwist angle. In some variations, the twist angle can be about 45degrees. In other variations, the twist angle can be about 60 degrees orabout 30 degrees.

The distal sensing portion can be covered by a sensor housing. Thesensor housing can have a housing diameter. The housing diameter can bebetween about 3.0 mm to about 10.0 mm. For example, the housing diametercan be about 5.0 mm. The sensor housing can also have a housing lengthdimension between about 40.0 mm to 50.0 mm.

In some variations, the microcontroller can be housed within the handle.The distal sensing portion can further comprise one or more operationalamplifiers. The one or more operational amplifiers can be configured toamplify raw output signals from the at least one of the first proximalmagnetometer, the second proximal magnetometer, the first distalmagnetometer, and the second distal magnetometer before such signals aretransmitted to an analog-to-digital converter (ADC) or an ADC componentof the microcontroller within the handle.

The metal detection device can also comprise a flexible portion couplingor connecting the distal sensing portion to the shaft. The flexibleportion can be bendable and comprise a straightened configuration and abent configuration. The distal sensing portion can be positioned closerto the shaft when the flexible portion is in the bent configuration. Theflexible portion can be made in part of a thermoplastic elastomer. Forexample, the flexible portion can be made in part of Pebax®.

The handle can further comprise a trigger configured to control bendingof the flexible portion. The trigger can be connected to the flexibleportion by a pull cable extending through the shaft and the flexibleportion. Squeezing the trigger can pull the pull cable to bend theflexible portion toward the shaft.

The handle can further comprise a trigger potentiometer coupled to thetrigger. The one or more processors of the microcontroller can beprogrammed to execute instructions to determine a trigger speed based ondata obtained from the trigger potentiometer.

The shaft can be rotatable with respect to a longitudinal axis of theshaft. The handle can also comprise a clocking ring coupled to theshaft. The shaft can be rotatable in response to a rotation of theclocking ring.

The handle can further comprise a locking ring. The locking ring cancomprise a plurality of locking splines configured to obstruct theclocking ring from rotating. The clocking ring can be configured to bepushed in a distal direction to free the clocking ring from the lockingsplines of the locking ring. The clocking ring can be rotatable afterbeing pushed in the distal direction.

The metal detection device can also comprise a test rod configured totranslate into and retract out of a sensor housing covering the distalsensing portion. The test rod can be used to verify a functionality ofthe metal detection device. In some variations, the test rod can be madein part of a ferromagnetic metal.

The test rod can be partially housed within a spring tube. The springtube can extend through the shaft and a flexible portion coupling theshaft to the distal sensing portion. The flexible portion can bebendable such that a flexible portion distal end bends toward the shaftwhen a trigger on the handle is squeezed. The spring tube can beconfigured to bias the flexible portion back to an unbent configurationwhen the trigger is released.

The spring tube can be made in part of a thermoplastic. For example, thespring tube can be made in part of polyethylene terephthalate.

The handle can further comprise a test rod slider. The test rod slidercan be configured to be actuated distally or proximally to translate thetest rod axially within the shaft. The handle can also comprise a sliderpotentiometer coupled via gears to part of the test rod slider. The oneor more processors of the microcontroller can be programmed to executefurther instructions to determine a slider position based on dataobtained from the slider potentiometer. The slider position can beindicative of a relative positioning of the test rod with respect to atleast one of the first proximal magnetometer, the second proximalmagnetometer, the first distal magnetometer, and the second distalmagnetometer.

The one or more processors of the microcontroller can be programmed toexecute further instructions to adjust the threshold when the test rodis positioned in proximity to at least one of the first proximalmagnetometer, the second proximal magnetometer, the first distalmagnetometer, and the second distal magnetometer in order to test anoperability or functionality of the metal detection device.

The handle can comprise a sensitivity wheel. The one or more processorsof the microcontroller can be programmed to execute further instructionsto adjust the threshold in response to a rotation of the sensitivitywheel. The handle further comprise a sensitivity rotary potentiometercoupled to the sensitivity wheel. The one or more processors of themicrocontroller can be programmed to execute instructions to determine awheel rotational direction based on data obtained from the sensitivityrotary potentiometer.

The one or more processors of the microcontroller can be programmed toexecute further instructions to apply either the signal filter or thederivative to the differential signal calculated based on the wheelrotational direction. The one or more processors of the microcontrollercan be programmed to execute additional instructions to adjust thethreshold based on the wheel rotational direction.

In some implementations, the one or more processors of themicrocontroller can be programmed to execute further instructions toapply both the signal filter and the derivative to the differentialsignal calculated based on the wheel rotational direction. The one ormore processors of the microcontroller can be programmed to executeadditional instructions to adjust the threshold based on the wheelrotational direction.

The distal sensing portion can further comprise an inertial measurementunit (IMU) comprising a three-axis accelerometer and a three-axisgyroscope. In some implementations, an IMU can also be housed within thehandle. The one or more processors of the microcontroller can beprogrammed to execute further instructions to adjust the threshold basedon acceleration data obtained from the three-axis accelerometer androtational data obtained from the three-axis gyroscope.

The distal sensing portion can comprise a distal light-emitting diode(LED) and the handle can comprise a proximal LED. At least one of thedistal LED and the proximal LED can be an instance of the outputcomponent and lights emitted by the at least one of the distal LED andthe proximal LED can be an instance of the user output.

The handle can comprise a speaker. The speaker can be another instanceof the output component. Sound (e.g., a beeping sound) transmitted bythe speaker can be an instance of the user output.

The distal sensing portion can be housed within a sensor housing. Thesensor housing and the shaft can be made of a biocompatible material toallow for intracorporeal detection within a body of a patient.

The shaft can be made in part of stainless steel. The sensor housing canbe made in part of at least one of titanium and a polymeric material. Inother variations, the sensor housing can be made in part of aluminum oraluminum alloy.

At least one of the first proximal magnetometer, the second proximalmagnetometer, the first distal magnetometer, and the second distalmagnetometer can be an anisotropic magnetoresistance (AMR) sensor. Thefirst proximal magnetometer can be separated from the second proximalmagnetometer by a proximal magnetometer separation distance. Theproximal magnetometer separation distance can be between about 4.00 mmand 5.00 mm.

The first distal magnetometer can be separated from the second distalmagnetometer by a distal magnetometer separation distance. The distalmagnetometer separation distance can be between about 4.00 mm and 5.00mm.

The second distal magnetometer can be separated from the first proximalmagnetometer by a gradiometer separation distance. The gradiometerseparation distance can be between about 18.00 mm and 20.00 mm.

The handle can be sized to allow the handle to be grasped with one hand.

In some variations, the detected object can be a surgical needle. Thedetected object can also be a portion of a metallic surgical equipment.Moreover, the detected object can be at least one of an RFID-taggedsponge and a metallic-marked sponge. The distal sensing portion canfurther comprise an RFID reader configured to read an RFID tag embeddedwithin the RFID-tagged sponge.

The detected object can be at least one of a non-ferromagnetic medicalequipment tagged with a ferromagnetic tag or plate. The detected objectcan also be at least one of a surgical wire, a guidewire, and anintravascular wire. The detected object can be a stent, a vascularscaffold, or a combination thereof.

The metal detection device can also comprise a conductive elementextending from at least one of the distal sensing portion and the shaft.A linking cable can be electrically coupled to the conductive element.The linking cable can extend out of the handle of the metal detectiondevice. The linking cable can be coupled to a closed-circuit indicator.

A metal detection system is disclosed comprising a magnetic blanketconfigured to cover a body part of a patient and the metal detectiondevice disclosed herein. As previously discussed, the metal detectiondevice can comprise a handle, a shaft extending from the handle, and adistal sensing portion comprising a plurality of magnetometers. Thedistal sensing portion can be covered by a sensor housing.

The metal detection device can further comprise an output componentconfigured to generate a user output to alert a user of a detectedobject based on magnetic field measurements obtained from the pluralityof magnetometers. At least one of the shaft and the sensor housing canbe configured to be inserted into the body part of the patient when thebody part is covered by the magnetic blanket.

A method of detecting a magnetic object within a body of a patient isalso disclosed. The method can comprise introducing a part of the metaldetection device into the body of the patient. As previously discussed,the metal detection device can comprise a handle, a shaft extending fromthe handle, a microcontroller comprising one or more processors andmemory units, an output component, and a distal sensing portionpositioned distally of the shaft.

The distal sensing portion can comprise a proximal gradiometer and adistal gradiometer. The proximal gradiometer can comprise a firstproximal magnetometer and a second proximal magnetometer. The distalgradiometer can comprise a first distal magnetometer and a second distalmagnetometer.

The method can further comprise calculating, using the one or moreprocessors, a differential signal from magnetic field measurementsobtained from the first proximal magnetometer, the second proximalmagnetometer, the first distal magnetometer, and the second distalmagnetometer. The method can also comprise applying, using the one ormore processors, at least one of a signal filter and a derivative to thedifferential signal calculated to obtain a detection signal. When aderivative is taken of the differential signal, the method can furthercomprise scaling down the derivative of the differential signal with amotion blocking signal.

The method can also comprise comparing, using the one or moreprocessors, the detection signal against a sensitivity or detectionthreshold. The method can further comprise generating a user output,using the output component, when the detection signal exceeds thesensitivity or detection threshold.

Another method of detecting a magnetic object within a body of a patientis also disclosed. The method can comprise introducing a part of themetal detection device into the body of the patient. As previouslydiscussed, the metal detection device can comprise a handle, a shaftextending from the handle, a distal sensing portion positioned distallyof the shaft, a flexible portion connecting the shaft to the distalsensing portion, a microcontroller comprising one or more processors andmemory units, and an output component. The distal sensing portion cancomprise a plurality of magnetometers.

The method can also comprise squeezing a trigger on the handle to bendthe flexible portion when the distal sensing portion and at least partof the flexible portion are within the body of the patient. The methodcan further comprise calculating, using the one or more processors, adetection signal from magnetic field measurements obtained from theplurality of magnetometers. The method can also comprise comparing,using the one or more processors, the detection signal against athreshold. The method can further comprise generating a user output,using the output component, when the detection signal exceeds thethreshold.

Another method of testing a functionality of a metal detection device isdisclosed. The method can comprise providing a metal detection device.The metal detection can comprise a handle, a shaft extending from thehandle, a microcontroller comprising one or more processors and memoryunits, an output component, a distal sensing portion positioned distallyof the shaft, and a sensor housing covering the distal sensing portion.The distal sensing portion can comprise a plurality of magnetometers.

The method can also comprise sliding a test rod slider on the handle ina distal direction toward the shaft. Sliding the test rod slider cancause a distal segment of a test rod housed within a lumen extendingthrough the shaft to be translated into the sensor housing. The methodcan further comprise calculating, using the one or more processors, adetection signal from magnetic field measurements obtained from theplurality of magnetometers when the distal segment of the test rod istranslated into the sensor housing.

The method can also comprise comparing, using the one or moreprocessors, the detection signal against a threshold. The method canfurther comprise generating a user output, using the output component,when the detection signal exceeds the threshold. The method can alsocomprise adjusting the threshold when the distal segment of the test rodis within the sensor housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an isometric view of a metal detection device.

FIG. 1B illustrates a side view of the metal detection device.

FIG. 2A illustrates an isometric view of a handle of the metal detectiondevice.

FIG. 2B illustrates a side view of the handle of the metal detectiondevice.

FIG. 3A illustrates a flexible portion of the metal detection device ina straightened configuration.

FIG. 3B illustrates a flexible portion of the metal detection device ina bent configuration.

FIG. 4A illustrates a side view of the handle of the metal detectiondevice with a left handle casing removed.

FIG. 4B illustrates a close-up side view of the handle of the metaldetection device with the left handle casing removed.

FIG. 5A illustrates an isometric view of a distal segment of the metaldetection device with a sensor housing and the flexible portion removedand a test rod in a retracted configuration.

FIG. 5B illustrates an isometric view of the distal segment of the metaldetection device with the sensor housing and the flexible portionremoved and the test rod in an extended configuration.

FIG. 5C illustrates a top plan view of the distal segment of the metaldetection device with the sensor housing and the flexible portionremoved and the test rod in the extended configuration.

FIG. 5D illustrates a sectional view of the distal segment of the metaldetection device along section A-A shown in FIG. 5C.

FIG. 6A illustrates a close up of the distal sensing portion of themetal detection device with the sensor housing removed.

FIG. 6B illustrates a close-up perspective view of the distal sensingportion of the metal detection device with the sensor housing removed.

FIG. 7A illustrates an isometric view of another variation of the distalsensing portion of the metal detection device with the sensor housingremoved.

FIG. 7B illustrates a close-up isometric view of the distal sensingportion of FIG. 7A.

FIG. 7C illustrates another variation of the distal sensing portion witha sensor housing covering the distal sensing portion.

FIG. 8A illustrates a rear close-up isometric view of a clocking ring ofthe metal detection device in a locked position.

FIG. 8B illustrates a rear close-up isometric view of the clocking ringin an unlocked position.

FIG. 8C illustrates a close-up side view of the clocking ring in thelocked position.

FIG. 8D illustrates a sectional view of the clocking ring in the lockedposition along section C-C shown in FIG. 8C.

FIG. 8E illustrates a close-up side view of the clocking ring in theunlocked position.

FIG. 8F illustrates a sectional view of the clocking ring in theunlocked position along section D-D shown in FIG. 8E.

FIG. 8G illustrates a front close-up isometric view of the clocking ringin the locked position with a nose cap removed.

FIG. 8H illustrates a front close-up isometric view of the clocking ringin the unlocked position with the nose cap removed.

FIG. 9A is a black-and-white image of a variation of the metal detectiondevice used to detect a surgical needle in a porcine bowel.

FIG. 9B is a black-and-white image of forceps used to retrieve thesurgical needle upon detection by the metal detection device.

FIG. 10A illustrates a variation of the metal detection device used todetect RFID-tagged sponges or sponges having one or more metallicmarkers within a body of a patient.

FIG. 10B illustrates the metal detection device used to detect wireswithin the body of a patient.

FIG. 11A illustrates a variation of the metal detection device used todetect a wire within a body of a patient through a closed-circuitdetection mechanism.

FIG. 11B illustrates the metal detection device used to detect a stentor other implantable scaffold within a body of a patient.

FIG. 12 illustrates a variation of a magnetic blanket or shield used toat least partially cover or shield a body cavity or body part of apatient when the metal detection device is undertaking magneticdetection within the body cavity or body part.

FIG. 13 is a signal diagram illustrating the distal sensing portion ofthe metal detection device passing over a surgical needle.

FIG. 14 is a signal diagram illustrating a test rod being extended and asensitivity level of the metal detection device being adjusted.

FIG. 15 is a signal diagram illustrating a distal sensing portion of themetal detection device passing over part of a metal guidewire.

FIG. 16A is a signal diagram illustrating the effects on a detectionsignal as the trigger of the metal detection device is pulled.

FIG. 16B is a signal diagram illustrating the metal detection deviceautomatically raising a sensitivity threshold or detection threshold inresponse to the trigger pulling scenario shown in FIG. 16A.

FIG. 16C is another signal diagram illustrating the metal detectiondevice automatically raising the sensitivity threshold or detectionthreshold in response to the trigger pulling scenario shown in FIG. 16A.

FIGS. 17A and 17B are signal diagrams illustrating a motion blocking orblocker signal used to scale down the detection signal in the event adistal sensing portion of the metal detection device is subjected tosudden motions.

FIG. 18 illustrates a method of detecting a magnetic object within thebody of a patient.

FIG. 19 illustrates another method of detecting a magnetic object withinthe body of a patient.

FIG. 20 illustrates a method of testing a functionality of a metaldetection device.

DETAILED DESCRIPTION

FIGS. 1A-1B illustrate a metal detection device 100 comprising a handle102, a shaft 131 extending from the handle 102, and a distal sensingportion 136 positioned distally of the shaft 131. The distal sensingportion 136 can be covered by a sensor housing 141. The metal detectiondevice 100 can also be referred to as a sharps finder, a surgical metaldetector, an RSI detector, or any combination thereof.

The distal sensing portion 136 can serve as a distal tip or distal endof the device 100. As shown in FIGS. 1A-1B, a flexible portion 145 canconnect the shaft 131 to the distal sensing portion 136 or the sensorhousing 141 of the distal sensing portion 136. As will be discussed inmore detail in the following sections, the flexible portion 145 can beconfigured to bend or curve such that the distal sensing portion 136 isbrought closer to the shaft 131 when the flexible portion 145 is bent.

FIG. 1A also illustrates that the shaft 131 is rotatable with respect toa longitudinal axis 104 of the shaft 131. The bending of the flexibleportion 145 and the rotation of the shaft 131 can allow an operator ofthe device 100 (e.g., a surgeon or other medical professional) toundertake intracorporeal detection of RSIs or other ferromagneticobjects by navigating through bodily lumen or around organs of thepatient.

The sensor housing 141, the flexible portion 145, and the shaft 131 canbe made of a biocompatible material. In some variations, the shaft 131can be made in part of a metallic material, a polymeric material, or acombination thereof. The shaft 131 can be made in part of aferromagnetic metal. The shaft 131 can be made in part of stainlesssteel.

The sensor housing 141 can be made of a material that does not interferewith magnetic field measurements undertaken by sensors within the sensorhousing 141. In some variations, the sensor housing 141 can be made of anon-ferromagnetic metallic material, a polymeric material, or acombination thereof. For example, the sensor housing 141 can be made inpart of titanium. In other variations, the sensor housing 141 can bemade in part of aluminum or an aluminum alloy. In additional variations,the sensor housing 141 can be made in part of a liquid crystal polymer.The sensor housing 141 can be made in part of a surgical or medicalgrade polytetrafluoroethylene (PTFE), polycarbonate (PC), polyetherether ketone (PEEK), or a combination thereof.

The flexible portion 145 can be made in part of a biocompatibleelastomeric material. In some variations, the flexible portion 145 canbe made in part of a thermoplastic elastomer. For example, the flexibleportion 145 can be made in part of a polyether block amide. Morespecifically, the flexible portion 145 can be made in part of PEBAX®. Inother variations, the flexible portion 145 can be made of a surgicalgrade rubber.

FIG. 1B illustrates that the sensor housing 141 can have a housinglength dimension 140. The housing length dimension can be between about40.0 mm to about 50.0 mm. For example, the housing length dimension 140can be about 45.0 mm (more specifically, about 45.70 mm).

In other variations, the housing length dimension 140 can be less than40.0 mm or greater than 50.0 mm. As will be discussed in more detail inthe following sections, the sensor housing 141 can be sized to fit twogradiometers or at least four magnetometers, a plurality of operationalamplifiers, an inertial measurement unit, a LED, and other electroniccomponents.

The flexible portion 145 can have a flexible portion length dimension146. The flexible portion length dimension 146 can be between about 40.0mm to about 60.0 mm. In some variations, the flexible portion lengthdimension 146 can be about 50.0 mm. For example, the flexible portionlength dimension 146 can be about 50.8 mm.

The shaft 131 can have a shaft length dimension 132. The shaft lengthdimension 132 can be a length of the exposed segment of the shaft 131.The shaft length dimension 132 can between about 300.0 mm to about 400.0mm. In some variations, the shaft length dimension 132 can be betweenabout 325.0 mm to about 375.0 mm. For example, the shaft lengthdimension 132 can be about 350.0 mm.

A segment of the shaft 131 can extend into the handle 102. The entirelength of the shaft 131 can be between about 400.0 mm to about 500.0 mm(e.g., about 450.0 mm) when including the segment of the shaft 131within the handle 102.

The shaft 131 can be hollow or include at least one lumen suitable forcables, rods, wires, or communication lines to pass through the shaft131 and permit mechanical and/or electrical communication between thehandle 102 and the distal sensing portion 136, the flexible portion 145,or a combination thereof. In other variations, the shaft 131 cancomprise multiple lumens.

The shaft 131 can be entirely rigid along its length. In othervariations, the shaft 131 can be flexible along its entire length suchthat the shaft can bend or conform to the shape of a bodily lumen. Theshaft 131 can be rigid except for one or more regions of flexibilityalong its length.

In some variations, the shaft 131 can be directly connected to thedistal sensing portion 136 or the sensor housing 141 covering the distalsensing portion 136 without the flexible portion 145. In othervariations, the device 100 can comprise multiple instances of theflexible portion 145 such that a distal segment of the device 100 beyondthe shaft 131 can bend in multiple directions. In some variations, themultiple instances of the flexible portion 145 can be interspersed alongthe length of the shaft 131 such that rigid segments of the shaft 131are connected by flexible portion 145.

The handle 102 can comprise a left handle casing 101 and a right handlecasing 103. The left handle casing 101 and the right handle casing 103can be coupled together via fasteners (e.g., screws), adhesive, aninterference fit, or a combination thereof to form the handle 102. Thehandle 102 can comprise a handle cavity for housing certain electronicand/or mechanical components for operating the device 100. The handle102 can be sized to allow the handle 102 to be grasped with one hand.

The handle 102, including the left handle casing 101 and the righthandle casing 103, can be made in part of a polymeric material, ametallic material, or a combination thereof. For example, the handle 102can be made of a rigid polymeric material such as polycarbonate.

It should be appreciated that there is no limitation to the actual size,shape, or configuration of the handle 102, the shaft 131, the flexibleportion 145, the sensor housing 141, or a combination thereof. Forexample, the device 100 can be designed or sized for hand-held use by asurgeon or other medical professional such that the handle 102 can begrasped by one hand of the surgeon or medical professional. In othervariations, the device 100 can be modified specifically forimplementation via a robotic surgical system such that any portion ofthe device 100 can be integrated with or is easily graspable by arobotic arm.

FIGS. 2A-2B illustrate that the handle 102 can comprise a trigger 105, aclocking ring 107, a nose cap 109, one or more sensitivity wheels 115, atest rod slider 117, and a light transmittance window 147. The trigger105 can be positioned on an underside of the handle 102. The trigger 105can be protected by a trigger guard 106.

As will be discussed in more detail in the following sections, a usercan squeeze the trigger 105 to control the bending of the flexibleportion 145. The flexible portion 145 can be bent up to 90° (see, forexample, FIG. 3B) or beyond in response to a squeezing of the trigger105. When the flexible portion 145 is bent, the distal sensing portion136 can be positioned closer to a distal end of the shaft 131.

The metal detection device 100 can be configured to undertakeintracorporeal detection of ferromagnetic RSIs or other ferromagneticobjects even when the flexible portion 145 is bent. For example, themetal detection device 100 can be configured to undertake intracorporealdetection of ferromagnetic RSIs or other items even when the flexibleportion 145 is bent between about 1° to about 90° or beyond 90°. Onetechnical problem with traditional surgical metal detectors is that suchdetectors are often rigid and inflexible and an operator of such adetector (e.g., a surgeon or other medical professional) can onlymanipulate the detector by translating it axially or rotating thedetector along its longitudinal axis by hand. This limits the range ofmotion of such detectors and their detection capability. For example,such detectors often cannot detect around organs or cannot extend intocertain vessels. One technical advantage offered by the metal detectiondevice 100 disclosed herein is the ability to undertake detection evenwhen part of the elongated segment of the device 100 is bent or curved.

The clocking ring 107 can be configured to rotate when urged into anunlocked position. The clocking ring 107 can be coupled to the shaft131. Rotating the clocking ring 107 can rotate the shaft 131. Rotatingand unlocking the clocking ring 107 will be discussed in more detail inthe following sections.

The nose cap 109 can serve as a distal cap of the handle 102. The nosecap 109 can also serve as a receiving and bearing surface for theclocking ring 107 when the clocking ring 107 rotates.

The one or more sensitivity wheels 115 and the test rod slider 117 canbe positioned above the trigger 105 to allow for an operator (e.g., asurgeon or other medical professional) to manipulate the test rod slider117, the sensitivity wheel 115, or a combination thereof while theoperator is holding the handle 102 and squeezing the trigger 105 at thesame time.

FIG. 2A illustrates that the device 100 can comprise two sensitivitywheels 115 positioned on opposite lateral sides of the test rod slider117. This can allow the device 100 to be easily held and manipulated byboth right-handed and left-handed operators.

The sensitivity wheel(s) 115 can be dialed (e.g., rotated forward ordistally and rotated backward or proximally) to adjust a detectionsensitivity. As will be discussed in more detail in the followingsections, adjusting the sensitivity wheel(s) 115 can adjust a detectionsensitivity of the device 100. For example, adjusting the sensitivitywheel(s) 115 can raise or lower a programmed threshold of detection.Also, for example, adjusting the sensitivity wheel(s) 115 can adjust amode of operation of the device 100 such that detection signals areprocessed in different ways. Moreover, an operator or user of the device100 can also switch between different modes of operation (e.g., a highspeed and high sensitivity mode or a low speed and low sensitivity mode)during the course of a detection.

The test rod slider 117 can be slid forward (distally) or backward(proximally) to translate a test rod 133 (see e.g., FIGS. 4A-4B and5B-5D) into or out of the sensor housing 141. The test rod slider 117can be mounted between the left handle casing 101 and the right handlecasing 103. The test rod 133 and the test rod slider 117 will bediscussed in more detail in the following sections.

The light transmittance window 147 can allow the light generated by alighting component (e.g., an LED) within the handle 102 to be madevisible to an operator. The light transmittance window 147 can also bereferred to as a light pipe or light bar. The light transmittance window147 can be made of a light-transmitting polymeric material (e.g., anacrylic polymer), a ceramic material, or a combination thereof. Thelight viewable through the light transmittance window 147 can provideuseful information to an operator concerning a battery life, a standbyindication, an error warning, a detection status, or a combinationthereof.

FIGS. 3A and 3B illustrate the flexible portion 145 of the device 100 ina straightened configuration 142 and a bent configuration 144,respectively. As shown in FIG. 3B, the distal sensing portion 136 can bepositioned closer to the shaft 131 (i.e., a distal segment of the shaft131) when the flexible portion 145 is in the bent configuration 144.

The flexible portion 145 can be bracketed by a distal tube fitting 139and a proximal tube fitting 143. The distal tube fitting 139 can couplethe flexible portion 145 to the distal sensing portion 136 or the sensorhousing 141 covering the distal sensing portion 136. The proximal tubefitting 143 can couple the flexible portion 145 to the shaft 131. Thedistal tube fitting 139 and the proximal tube fitting 143 can serve asends of the flexible portion 145.

As will be discussed in more detail in the following sections, a pullcable 135 (see, for example, FIGS. 4B and 5D) within the shaft 131 canrun the lengths of the shaft 131 and the flexible portion 145 and adistal end of the pull cable 135 can be grounded or otherwise coupled tothe distal tube fitting 139. For example, the pull cable 135 can bethread through a hole defined in the distal tube fitting 139 and a knotcan be tied to secure the distal end of the pull cable 135 to the distaltube fitting 139. In other variations, a ferrule or other type of ring,cap, or clip can be used to affix the distal end of the pull cable tothe distal tube fitting 139.

A proximal end of the pull cable 135 can be coupled to the trigger 105.For example, the proximal end of the pull cable 135 can be wound arounda spool within the trigger 105.

Squeezing the trigger 105 can pull the pull cable 135 and bend theflexible portion 145 into the bent configuration 144. The flexibleportion 145 can be flexible enough to allow flexure in any desireddirection.

When the trigger 105 is released, the flexible portion 145 can be biasedback into the straightened configuration 142 by one or more structureswithin the flexible portion 145. For example, the flexible portion 145can be biased or otherwise pushed back into the straightenedconfiguration 142 by a spring tube 137 (see, for example, FIGS. 4A-4B,5A-5B, and 5D) extending through the flexible portion 145.

The flexible portion 145 can be bent up to 90° or beyond in response toa squeezing of the trigger 105. For example, the flexible portion 145can be bent about 30°, about 45°, about 60°, or about 90° with respectto its straightened configuration 142 when the trigger 105 is squeezed.The flexible portion 145 can also be bent about 95°, about 100°, about105°, about 110°, about 115°, or about 120° when the trigger 105 issqueezed even harder.

In other variations, the trigger 105 can be replaced with another typeof mechanical actuator such as one or more levers, wheels, knobs, pulls,or a combination thereof. In additional variations, the trigger 105 canbe replaced with an electrical actuator such as one or more buttons,switches, or a combination thereof.

FIGS. 3A and 3B also illustrate that the sensor housing 141 can have ahousing diameter 138. The housing diameter 138 can be between about 3.0mm to about 10.0 mm. For example, the housing diameter 138 can be about5.0 mm.

The flexible portion 145 can have a flexible portion diameter. Theflexible portion diameter can be between about 3.0 mm to about 10.0 mm.For example, the flexible portion diameter can be about 5.0 mm.

The shaft 131 can have a shaft diameter. The shaft diameter can bebetween about 3.0 mm to about 10.0 mm. For example, the shaft diametercan be about 5.0 mm.

When the housing diameter 138, the flexible portion diameter, and theshaft diameter are all about 5.0 mm, the elongate segment of the device100 (including the sensor housing 141, the flexible portion 145, and theshaft 131) can fit within a standard surgical trocar. This can allow thedevice 100 to be used for laparoscopic surgeries, open surgeries, orrobotic surgeries.

FIG. 4A illustrates a side view of the handle 102 with the left handlecasing 101 removed in order to view certain components and mechanismswithin the handle 102. FIG. 4A illustrates that the handle 102 cancomprise a handle printed circuit board (PCB) 123. The handle PCB 123can extend from a handle grip 114 of the handle 102 to a handle barrel116.

The handle PCB 123 can be a rigid PCB. In other variations, the handlePCB 123 can be a flexible PCB.

The handle PCB 123 can serve as the main circuit board for electroniccomponents housed within the handle 102. As shown in FIG. 4A, amicrocontroller 185, a speaker 181, and certain potentiometers can becoupled to the handle PCB 123.

The microcontroller 185 can comprise one or more processors and memoryunits. The one or more processors of the microcontroller 185 can beprogrammed to execute instructions stored in the memory units to, amongother things, determine a motion of certain components of the device100, test a functionality of the device 100, obtain and processdetection signals based on magnetic field measurements made by themagnetometers, and detect an RSI or other ferromagnetic object based onsuch processed detection signals.

In some variations, the microcontroller 185 can be a low-power reducedinstruction set computer based (RSIC-based) microcontroller. Themicrocontroller 185 can be an 8-bit microcontroller. In othervariations, the microcontroller can be a 16-bit or 32-bitmicrocontroller. For example, the microcontroller 185 can be theATmega32U4 microcontroller distributed by Microchip Technology Inc.

The microcontroller 185 can comprise flash memory, static random-accessmemory (SRAM), electrically erasable programmable read-only memory(EEPROM), or a combination thereof. For example, the microcontroller 185can comprise at least 32 kilobytes (KB) of flash memory, 2.5 KB of SRAM,and 1 KB of EEPROM.

The microcontroller 185 can have a CPU speed of at least 16 MIPS at 16MHz. In other variations, the microcontroller 185 can have a CPU speedof 28 MIPS at 33 MHz or 36 MIPS at 40 MHz.

The microcontroller 185 can also comprise an analog-to-digital converter(ADC). For example, the microcontroller 185 can comprise a 12-channel10-bit ADC. In other variations, the microcontroller 185 can comprise a12-bit ADC or a 16-bit ADC. The ADC can convert voltage data obtainedfrom the magnetometers (0V to about 5V) to digital data. For example,voltage data obtained from the magnetometers and other sensors can beconverted to arbitrary signal bin units (see, e.g., FIGS. 13-17B).

Although not shown in FIGS. 4A and 4B, it is contemplated by thisdisclosure that the handle 102 can also comprise an inertial measurementunit (IMU). The IMU can provide up to six degrees of freedom (DoF). TheIMU can be a 6-axis IMU comprising a 3-axis accelerometer and a 3-axisgyroscope. The IMU can measure tilt and angular rates and accelerationsin three perpendicular axes. In some variations, the IMU can be alow-power and low-noise 16-bit IMU. For example, the IMU can be BMI055,MBI088, or BMI160 IMU provided by Bosch Sensortec GmbH. The IMU can beanother instance of the IMU 159 shown in FIGS. 6 and 7A-7C. The IMU canbe a handle PCB 123.

Data obtained from the IMU can be used as part of any calculationsconcerning a motion of the handle 102. For example, data obtained fromthe IMU 159 as well as the potentiometers can be used to determinewhether an operator (e.g., a surgeon or other medical professional) hasshaken or wobbled the handle 102 or is moving the handle 102 toorapidly. One or more processors of the microcontroller 185 can beprogrammed to execute further instructions to disregard a sudden motionof the handle 102 or a motion exceeding one or more motion thresholdsbased on acceleration data obtained from the 3-axis accelerometer androtational data obtained from the 3-axis gyroscope.

The device 100 can comprise a number of output components coupled to thehandle PCB 123. The output components can include one or more lightsand/or audio components. The output components can be configured togenerate a user output (e.g., a sound and/or light) to alert a user of adetected RSI or ferromagnetic object. The output components can also beconfigured to generate a user output to indicate a functionality oroperational status of the device 100. For example, the user output canbe generated by the output components to convey information concerning abattery life of the device 100, a standby indication, an error warning,a detection status, or a combination thereof.

The output components can include a speaker 181, a proximallight-emitting diode (LED) 173, a distal LED 183 (see FIG. 6A), or acombination thereof. The speaker 181 and/or the proximal LED 173 can becoupled to the handle PCB 123. In other variations, only the speaker 181can be coupled to the handle PCB 123.

As shown in FIG. 4A, the speaker 181 can be positioned within the handlegrip 114. In other variations, the speaker 181 can be positioned withinthe handle barrel 116.

The speaker 181 can be configured to transmit a sound or audio messageto inform the operator of a detected RSI or other ferromagnetic objector to convey information concerning a functionality or operationalstatus of the device 100. For example, speaker 181 can generate a soundor audio message to convey information concerning a battery life of thedevice 100, a standby indication, an error warning, a detection status,or a combination thereof.

The sound can be a beeping sound, a ringing sound, a chime, a pitchedtonal sound, or a combination thereof. The audio message can be apre-recorded message or phrase.

The proximal LED 173 can be positioned within the handle barrel 116. Inother variations, the proximal LED 173 can be positioned in proximity tothe nose cap 109 or along the handle grip 114.

The handle 102 can further comprise a light transmittance window 147.The light transmittance window 147 can be positioned directly over theproximal LED 173 or close to the proximal LED 173. The lighttransmittance window 147 can allow a light generated by the proximal LED173 to be made visible to an operator. The light transmittance window147 can also be referred to as a light pipe or light bar. The lighttransmittance window 147 can be made of a light-transmitting polymericmaterial (e.g., an acrylic polymer), a ceramic material, or acombination thereof.

The device 100 can also comprise a distal LED 183. The distal LED 183can be coupled to a flexible circuit or circuit board in the distalsensing portion 136 (see FIG. 6A). The sensor housing 141 can comprise alight transmittance window or a light-transmitting portion to allowlight generated by the distal LED 183 to be made visible to an operatorvia endoscopy.

The distal LED 183 can function similarly to the proximal LED 173. Thesame light or light patterns generated by the proximal LED 173 can alsobe generated by the distal LED 183 (and vice versa). The light or lightpatterns generated by the proximal LED 173 and/or the distal LED 183 canconvey information concerning a battery life of the device 100, astandby indication, an error warning, a detection status, or acombination thereof.

For example, both the proximal LED 173 and the distal LED 183 cangenerate a green blinking light pattern (a heartbeat light pattern) toindicate that the device 100 is in operation. The proximal LED 173 cangenerate a red blinking light pattern to inform the operator that one ormore electronic components or sensors within the sensor housing 141 aredisconnected or the entire sensor housing 141 has broken off or isdisconnected. The speaker 181 can also generate a warning sound when theone or more electronic components or sensors within the sensor housing141 are disconnected or the entire sensor housing 141 has broken off oris disconnected.

The speaker 181 can also generate a beeping sound or beeping soundpattern when a detection signal is above a sensitivity or detectionthreshold to inform the operator that the device 100 has potentiallydetected an RSI or other ferromagnetic object. The sound (e.g., beepingsound or sound pattern) generated by the speaker 181 can correspond tothe size of the detection signal above the sensitivity or detectionthreshold. For example, the speaker 181 can generate a louder instanceof the beeping sound or sound pattern when the size of the detectionsignal above the sensitivity or detection threshold exceeds apredetermined size threshold. The proximal LED 173, the distal LED 183,or a combination thereof can also generate a light or light pattern(e.g., a sustained blue light or blinking blue light) when the detectionsignal is above the sensitivity or detection threshold. In somevariations, the brightness of the light or light pattern generated bythe proximal LED 173, the distal LED 183, or a combination thereof cancorrespond to the size of the detection signal above the sensitivity ordetection threshold. For example, the proximal LED 173, the distal LED183, or a combination thereof can generate a brighter instance of thelight or light pattern when the size of the detection signal above thesensitivity or detection threshold exceeds a predetermined sizethreshold.

FIG. 4A also illustrates that the device 100 can comprise a power sourceconfigured to supply power to the device 100 and its various electroniccomponents. In some variations, the power source can be a portable powersource such as one or more batteries 149. As shown in FIG. 4A, one ormore batteries 149 can be housed within the handle 102. For example, thehandle grip 114 can comprise a battery holder or battery holdingcompartment comprising a positive battery terminal 125 and a negativebattery terminal 127.

In some variations, the battery 149 can be a rechargeable battery. Inthese variations, the device 100 can comprise an input for receivingpower from an external power source to charge the battery 149. Inadditional variations, the device 100 can comprise an input forreceiving power from an external power source and the device 100 can bepowered completely by the external power source without batteries 149.

As shown in FIGS. 4A and 4B, the handle 102 can further comprise atrigger 105, a trigger potentiometer 171 coupled to at least part of thetrigger 105, and a trigger spring 121. A proximal segment of the pullcable 135 can be coupled to at least part of the trigger 105.

The trigger 105 can be actuated to control the bending of the flexibleportion 145. As previously discussed, the trigger 105 can be connectedto the flexible portion 145 by a pull cable 135 extending through theshaft 131 and the flexible portion 145. Squeezing the trigger 105 pullsthe pull cable 135 and bends the flexible portion 145. Bending theflexible portion brings the distal sensing portion 136 closer to theshaft 131.

As shown in FIG. 4B, the trigger 105 can comprise a pull cable hole 165.The pull cable 135 can extend through the pull cable hole 165 and betied or otherwise secured to the trigger 105 at the pull cable hole 165.In other variations, a proximal segment or end of the pull cable 135 canextend into a cavity within the trigger 105 and be wound around a spoolwithin the trigger 105. The pull cable 135 can also be attached to thetrigger 105 via adhesives, clips, ties, ferrules, or a combinationthereof.

As previously discussed, the pull cable 135 can run the length of theshaft 131 and the flexible portion 145 and a distal end of the pullcable 135 can be tied or otherwise coupled to the distal tube fitting139 at a distal end of the device 100.

For example, the pull cable 135 can be thread through a hole defined inthe distal tube fitting 139 and a knot can be tied to secure the distalend of the pull cable 135 to the distal tube fitting 139. In othervariations, a ferrule or other type of ring, cap, or clip can be used toaffix the distal end of the pull cable to the distal tube fitting 139.

In some variations, the pull cable 135 can be a braided cable or wiresuch as a braided stainless steel cable. In other variations, the pullcable 135 can be a polymeric cable or wire such as a nylon cable orwire.

The trigger spring 121 can spring load the trigger 105 such that thetrigger 105 returns to its starting position after being squeezed. Thetrigger spring 121 can be a torsion spring. The trigger spring 121 canmate with features on the interior of the handle 102 to provideresistance.

Squeezing the trigger 105 can pull the pull cable 135 and bend theflexible portion 145 into the bent configuration 144. The flexibleportion 145 can be flexible enough to allow flexure in any desireddirection.

When the trigger 105 is released, the flexible portion 145 can be biasedback into the straightened configuration 142 by one or more structureswithin the flexible portion 145. For example, the flexible portion 145can be biased or otherwise pushed back into the straightenedconfiguration 142 by a spring tube 137 (see, for example, FIGS. 4A-4B,5A-5B, and 5D) extending through the flexible portion 145.

In other variations, the trigger 105 can be replaced with another typeof mechanical actuator such as one or more levers, wheels, knobs, pulls,or a combination thereof. In additional variations, the trigger 105 canbe replaced with an electrical actuator such as one or more buttons,switches, or a combination thereof.

FIG. 4B illustrates a close-up side view of the handle 102 with the lefthandle casing 101, the trigger spring 121, and the sensitivity wheel 115removed for ease of viewing. FIG. 4B illustrates that a triggerpotentiometer 171 can be coupled to a rotatable portion of the trigger105. For example, the trigger potentiometer 171 can be coupled to atrigger axle (obscured in FIG. 4B) extending through the triggerpotentiometer 171.

The trigger potentiometer 171 can be a rotary potentiometer. In somevariations, the trigger potentiometer 171 can be mounted to part of thehandle PCB 123. In other variations, the trigger potentiometer 171 canbe mounted to another PCB within the handle 102.

The trigger potentiometer 171 can provide data concerning a triggerspeed (e.g., how fast the trigger is pulled). Since bending the flexibleportion 145 subjects the distal sensing portion 136 to sudden motionsand brings the distal sensing portion 136 closer to the ferromagneticshaft 131, the trigger potentiometer 171 provides data that can be usedto adjust a sensitivity threshold or detection threshold.

For example, the one or more processors of the microcontroller 185 canbe programmed to raise a sensitivity or detection threshold (i.e.,decrease a detection sensitivity) to account for any magnetic fielddistortions caused by the shaft 131 when the distal sensing portion 136is bent toward the shaft 131 and/or any sudden movements of the distalsensing portion 136. For example, data obtained from the triggerpotentiometer 171 can also be used to determine whether an operator hasjerked or yanked the distal sensing portion 136 by squeezing the trigger105 too forcefully or quickly.

Raising the sensitivity or detection threshold (also referred to aslowering or decreasing the detection or sensitivity level) can be doneto avoid false positive signals. When the trigger is squeezed orotherwise moves too quickly, this can create a sharp spike in themagnetic field detected. In these instances, the one or more processorsof the microcontroller 185 can be programmed to execute instructions todetermine that a trigger motion exceeds a trigger motion threshold ortrigger motion threshold range, the one or more processors can then beprogrammed to execute further instructions to raise the programmedsensitivity or detection threshold (i.e., lower the sensitivity level ofthe device 100) in response to the sudden or uncontrolled movement ofthe trigger 105. This can be done to forestall or tamper any falsepositive signals. In this manner, data obtained from the triggerpotentiometer 171 can be factored into detection algorithms run by themicrocontroller 185.

The handle 102 can further comprise one or more sensitivity wheels 115configured to adjust a programmed sensitivity or detection threshold inresponse to a rotation of the sensitivity wheel(s) 115. At least part ofthe sensitivity wheel(s) 115 can protrude out of cutout(s) defined alongthe handle casings to allow an operator to dial or rotate thesensitivity wheel(s) 115.

An operator can dial or rotate the sensitivity wheel 115 in order toraise or lower the programmed sensitivity or detection threshold. Forexample, an operator can dial or otherwise rotate at least one of thesensitivity wheels 115 forward (or in a distal direction) to increasethe sensitivity level of the device 100. Increasing the sensitivitylevel of the device 100 can allow the device 100 to more accuratelydetect the presence of small or weakly magnetized RSIs or otherferromagnetic objects within the body of the subject. Increasing thesensitivity level of the device 100 can decrease a programmedsensitivity or detection threshold.

The operator can dial or otherwise rotate at least one of thesensitivity wheels 115 backward (or in a proximal direction) to decreasethe sensitivity level of the device 100. Decreasing the sensitivitylevel of the device 100 can increase a programmed sensitivity ordetection threshold. The operator can decrease the sensitivity level ofthe device 100 when false positive signals from ferromagnetic medicalequipment in proximity to the patient (e.g., metallic surgical equipmentor carts) makes it difficult for the operator to perceive actualdetection signals.

The device 100 can comprise a number of discrete sensitivity levels. Forexample, the device 100 can comprise 11 discrete sensitivity levels witha default level being level 7. The device 100 can generate a user output(e.g., two successive beeps or beeping sounds) when the sensitivitylevel has reached either an upper (e.g., level 11) or lower limit (e.g.,level 1).

The sensitivity wheel(s) 115 can be rotationally coupled to asensitivity rotary potentiometer 169 (see FIG. 4B, the sensitivitywheels 115 are removed in FIG. 4B for ease of viewing). The sensitivityrotary potentiometer 169 can be coupled to the handle PCB 123.

The sensitivity rotary potentiometer 169 can provide data concerning awheel rotation and, thereby, a sensitivity level desired by theoperator.

The one or more processors of the microcontroller 185 can be programmedto execute instructions to smooth out potentiometer signals obtainedfrom the sensitivity rotary potentiometer 169 to reduce signal noise andto observe such signals for consecutive up or down signal spikes as aresult of the operator dialing at least one of the sensitivity wheels115 forward or backward. The one or more processors of themicrocontroller 185 can be programmed to execute instructions to adjusta sensitivity or detection threshold when either two consecutivesensitivity upward signal spikes or two consecutive downward signalspikes are detected. For example, the one or more processors of themicrocontroller 185 can be programmed to execute instructions to lowerthe sensitivity or detection threshold (i.e., increase the sensitivitylevel) when two consecutive upward signal spikes from the sensitivityrotary potentiometer 169 are observed.

The sensitivity level of the device 100 can also be adjusted by thedevice 100 automatically (i.e., without the operator's input). Forexample, the sensitivity level of the device 100 can be decreased andthe sensitivity or detection threshold can be increased if a triggermotion calculated from data obtained from the trigger potentiometer 171exceeds a trigger motion threshold. Also, for example, the sensitivitylevel of the device 100 can be decreased and the sensitivity ordetection threshold can be increased when the magnetometers areperiodically reset to filter out any settling events or level changes.For example, the magnetometers can be reset periodically (e.g., every 5seconds) using a mag reset function to realign the domains in themagnetometers with a current pulse. This is done in case themagnetometers are highly affected by a strong magnetic field. Resettingthe magnetometers can cause a transient signal spike or bump. Raisingthe sensitivity or detection threshold at the same time themagnetometers are reset can reduce the likelihood of false positivesignals.

Although sensitivity wheel(s) 115 are mentioned in the present examples,it is contemplated by this disclosure and it should be understood by oneof ordinary skill that the sensitivity wheel(s) 115 are just one exampleof a sensitivity actuator. In other variations, the sensitivity actuatorcan be implemented one or more sliders, knobs, buttons, switches, or acombination thereof. In additional variations, the sensitivity actuatorcan be implemented as user interface controls presented through anelectronic display or touchpad.

FIGS. 4A and 4B also illustrate that the handle 102 can comprise a testrod slider 117. In some variations, the test rod slider 117 can slidealong a dorsal side of the handle barrel 116. The test rod slider 117can be slid or otherwise translated forward (distally) or backward(proximally) in order to translate a test rod 133 axially within theshaft 131. Sliding the test rod slider 117 forward can extend or drive adistal end of the test rod 133 into the sensor housing 141 and inproximity to the magnetometers of the distal sensing portion 136.

The test rod 133 can be made in part of a ferromagnetic material. Forexample, the test rod 133 can be made in part of a ferromagnetic metal.The test rod 133 can be made in part of a magnetic stainless steel suchas a ferritic stainless steel, martensitic stainless steel, or duplexstainless steel.

The test rod 133 can be flexible and bendable. For example, the test rod133 can be implemented as a flexible ferromagnetic cable or rod.

The test rod 133 can have a known magnetic signature such that when thetest rod 133 is extended into the sensor housing 141, a magnetic fielddistortion caused by the test rod 133 can be accounted for. The test rod133 can be used to verify a functionality of the device 100 and/orre-zero a magnetic environment in-situ.

The test rod slider 117 can be spring-loaded by an extension spring 119to pull the test rod slider 117 back to its default starting position(see, for example, FIG. 4B) when a distal force is not applied to thetest rod slider 117. One end of the extension spring 119 can be groundedto the right handle 102 and the other end of the extension spring 119can be attached or coupled to at least part of the test rod slider 117.

A proximal end of the test rod 133 can be secured or otherwise coupledto the test rod slider 117. For example, the proximal end of the testrod 133 can be secured to a proximal portion of the test rod slider 117by adhesives, fasteners, ties, clips, or a combination thereof.

The test rod 133 can be partially housed within a spring tube 137. Adistal end of the test rod 133 can extend out of the spring tube 137. Aproximal end of the spring tube 137 can be secured or otherwise coupledto the right handle casing 103. For example, the proximal end of thespring tube 137 can be secured to features of the right handle casing103 by adhesives, fasteners, ties, clips, or a combination thereof. Thespring tube 137 can extend from the handle 102 through the shaft 131 andthe flexible portion 145.

In addition to serving as a housing for the test rod 133, the springtube 137 can also be used to bias the flexible portion 145 back to itsunbent configuration 144 when the trigger 105 is released. The springtube 137 can be made in part of polyethylene terephthalate (PET). Inother variations, the spring tube 137 can be made of a polymericmaterial or copolymer exhibiting shape-memory characteristics. Thespring tube 137 can also provide a degree of rigidity or structure tothe flexible portion 145.

One advantage of using the spring tube 137 to house the test rod 133 andbias the flexible portion 145 back to its unbent configuration 144 isthat the same component can serve multiple functions, thereby reducingthe total number of components running through a small-diameter shaft.This also helps to reduce the overall complexity of the device 100.

The handle 102 further comprises a slider potentiometer 167 mounted orotherwise coupled to the handle PCB 123. The slider potentiometer 167can be coupled via gears to at least part of the test rod slider 117.

For example, FIGS. 4A and 4B illustrate that the test rod slider 117 canbe coupled to a rack gear 128 configured to interact with a spur gear129. The spur gear 129 can be rotationally coupled to the sliderpotentiometer 167. For example, a gear axle extending from the spur gear129 can be coupled to the slider potentiometer 167.

Data obtained from the slider potentiometer 167 can be used to determinea slider position of the test rod slider 117. The slider position can beindicative of the relative positioning of the test rod 133 with respectto the magnetometers of the distal sensing portion 136. For example, theslider position can be indicative of the relative positioning of thetest rod 133 with respect to at least one of the first proximalmagnetometer 202, the second proximal magnetometer 204, the first distalmagnetometer 208, and the second distal magnetometer 210.

When the test rod 133 is driven by the test rod slider 117 into thesensor housing 141 and in proximity to the magnetometers, the one ormore processors of the microcontroller 185 can be programmed to executeinstructions to conduct certain detection diagnostics. For example, theone or more processors of the microcontroller 185 can be programmed toexecute instructions to compare magnetic field measurements obtainedfrom the magnetometers with known magnetic field values associated withthe ferromagnetic test rod 133.

The one or more processors of the microcontroller 185 can be programmedto execute further instructions to instruct the output component (e.g.,the speaker 181 or the LEDs) to generate a user output (e.g., a sound orlight pattern) to inform an operator of the results of the diagnostic.

The test rod 133 can be used in combination with the sensitivity wheel115 to gauge a functionality or operability of the device 100. Forexample, when an operator is not sure if the device 100 is functioningproperly, the operator can increase the sensitivity level of the device100 by dialing the sensitivity wheel 115 forward or in a distaldirection and pushing the test rod slider 117 forward to translate theferromagnetic test rod 133 into the sensor housing 141 and in proximityto the magnetometers. The operator can gain insight into thefunctionality of the device 100 based on the user output generated bythe device 100 in this scenario.

Data obtained from the slider potentiometer 167 can also be used as partof any calculations or determinations concerning a motion (e.g., speedand/or acceleration) of the test rod 133. For example, data obtainedfrom the slider potentiometer 167 can be used to determine whether anoperator has extended or retracted the test rod 133 too quickly.

The device 100 can also automatically increase the sensitivity levelwhen data obtained from the slider potentiometer 167 indicates that thetest rod slider 117 is being pushed forward to test the functionality ofthe device 100. The device 100 can automatically increase thesensitivity level (thereby decreasing the sensitivity or detectionthreshold) to increase the chance that the test rod 133 is detected bythe magnetometers. For example, the one or more processors of themicrocontroller 185 can be programmed to execute instructions todetermine that the test rod 133 is being advanced forward based on dataor signals obtained from the slider potentiometer 167. The one or moreprocessors of the microcontroller 185 can be programmed to executefurther instructions to lower the sensitivity or detection threshold inresponse to the test rod 133 being advanced forward or into the sensorhousing 141.

In other instances, the test rod 133 can be used to cancel out falsepositive signals or noise attributed to ferromagnetic objects in thesensing environment. For example, the test rod 133 can be used to cancelout false positive signals or noise attributed to ferromagnetic medicalequipment in proximity to the patient (e.g., metallic surgical equipmentor carts). Such noise can make it difficult for the operator to perceiveactual detection signals. For example, an operator desiring to re-zero amagnetic environment can apply a distal force to the test rod slider 117to extend the test rod 133 into the sensor housing 141 and maintain thetest rod 133 in this extended configuration for a period of time above apredetermined time threshold. In response to the test rod 133 beingmaintained in this extended configuration, the one or more processors ofthe microcontroller 185 can be programmed to execute instructions todecrease a sensitivity level of the device 100 by raising a sensitivityor detection threshold until most (or a significant number of) falsepositive signals are below the new sensitivity or detection thresholdexcept for signals attributed to the test rod 133. This new highersensitivity or detection threshold can then be maintained even when theoperator has let go of the test rod slider 117 and the test rod 133 isno longer extended into the sensor housing 141 and is in a retractedconfiguration. The operator can then undertake detection at this newlowered sensitivity level (i.e., with a higher sensitivity or detectionthreshold).

FIG. 5A illustrates an isometric view of a distal segment of the device100 with the sensor housing 141 and the flexible portion 145 removed forease of viewing and the test rod 133 in a retracted configuration 130.The retracted configuration 130 can be the default configuration of thetest rod 133. A distal end of the test rod 133 can be within the springtube 137 when in the retracted configuration 130. When in the retractedconfiguration 130, the test rod 133 can be sufficiently distanced fromthe magnetometers such that the magnetism of the test rod 133 does notsignificantly affect the detection of RSIs or other ferromagneticmetallic objects.

FIG. 5B illustrates an isometric view of the same distal segment of thedevice 100 shown in FIG. 5A but with the test rod 133 in an extendedconfiguration 134. The test rod 133 can be in the extended configuration134 when an operator has advanced the test rod slider 117 on the handle102 and is applying a distal force to the test rod slider 117 tomaintain the test rod slider 117 in the advanced position (e.g., bykeeping the operator's finger on the test rod slider 117). The distalend of the test rod 133 can be extended or advanced out of the springtube 137 into the sensor housing 141 (not shown in FIG. 5B for ease ofviewing) when the test rod 133 is in the extended configuration 134.When in the extended configuration 134, the test rod 133 can be in closeenough proximity to the magnetometers of the distal sensing portion 136such that the ferromagnetic test rod 133 is detectable by at least oneof the magnetometers (a magnetic field distortion caused by the test rod133 is detectable by at least one of the first proximal magnetometer202, the second proximal magnetometer 204, the first distal magnetometer208, and the second distal magnetometer 210).

The distal end of the test rod 133 can be separated from a secondproximal magnetometer 204 by several millimeters when the test rod 133is in the extended configuration 134. For example, the distal end of thetest rod 133 can be separated from the second proximal magnetometer bybetween about 1.0 mm to about 5.0 mm when the test rod 133 is in theextended configuration 134. In other variations, the distal end of thetest rod 133 can be separated from the second proximal magnetometer 204by between about 5.0 mm to about 10.0 mm when the test rod 133 is in theextended configuration 134. In other variations, the distal end of thetest rod 133 can be separated from the second proximal magnetometer bymore than 10.0 mm or less than 1.0 mm when the test rod 133 is in theextended configuration 134. In additional variations, the distal end ofthe test rod 133 can be positioned over one or more of the magnetometersbut not in contact with the magnetometers when the test rod 133 is inthe extended configuration 134.

For example, in some variations, the distal tip of the test rod 133 canbe positioned about 1.0 mm past the second proximal magnetometer 204when the test rod 133 is in the extended configuration 134.

In alternative variations, the distal tip of the test rod 133 can bepositioned about 1.0 mm past the first proximal magnetometer 202 whenthe test rod 133 is in the extended configuration 134.

In additional variations, the distal tip of the test rod 133 can bepositioned about 1.0 mm past the first distal magnetometer 208 or thesecond distal magnetometer 210 when the test rod 133 is in the extendedconfiguration 134. In these variations, the entire test rod 133 can bepositioned over the magnetometers.

FIG. 5C illustrates a top plan view of the distal segment of the device100 with the sensor housing 141 and the flexible portion 145 removed forease of viewing and the test rod 133 in the extended configuration 134.FIG. 5D illustrates a sectional view of the same distal segment alongsection A-A shown in FIG. 5C.

FIGS. 5C and 5D illustrate that an elongate flex circuit 157 can coupleone or more PCBs in the distal sensing portion 136 to the handle PCB123. For example, the elongate flex circuit 157 can couple a proximalrigid PCB 161 to the handle PCB 123. The elongate flex circuit 157allows the magnetometers, amplifiers, and other electronic componentswithin the distal sensing portion 136 to be in electrical communicationwith the microcontroller 185 mounted to the handle PCB 123. The segmentof the elongate flex circuit 157 extending through the flexible portion145 can bend or flex when the flexible portion 145 is pulled into thebent configuration 144 in response to squeezing of the trigger 105.

The elongate flex circuit 157 or flexible printed circuit can compriseconductive metallic foils printed, adhered, laminated, deposited, and/orotherwise bonded to a flexible polymeric film such as a PET film orpolyimide film. In other variations, the elongate flex circuit 157 canbe a rigid-flex PCB or a flexible printed circuit having some rigidity.

The elongate flex circuit 157 can be positioned in between the springtube 137 partially housing the test rod 133 and the pull cable 135within the flexible portion 145 and the shaft 131. The pull cable 135can be positioned closer to a bottom or ventral side of the flexibleportion 145 and the shaft 131.

As previously discussed, the distal end of the pull cable 135 can begrounded or otherwise coupled to the distal tube fitting 139. The distalend of the pull cable 135 can be grounded or otherwise coupled to thedistal tube fitting 139 below or inferior to the elongate flex circuit157 as shown in FIG. 5D.

For example, the pull cable 135 can be thread through a hole defined inthe distal tube fitting 139 and a knot can be tied to secure the distalend of the pull cable 135 to the distal tube fitting 139. In somevariations, the hole on the distal tube fitting 139 can be positionedbelow or inferior to the elongate flex circuit 157 as. In othervariations, a ferrule or other type of ring, cap, or clip can be used toaffix the distal end of the pull cable to the distal tube fitting 139.

The spring tube 137 can be positioned closer to a top or dorsal side ofthe flexible portion 145 and the shaft 131. As shown in FIG. 5D, adistal of the spring tube 137 can be coupled to the distal tube fitting139 above or superior to the elongate flex circuit 157.

One technical advantage of the arrangement of tubes, circuits, andcables within the flexible portion 145 is that the flexible portion 145can be bent quickly and effectively and can, just as easily, recover itsunbent or straightened configuration. For example, the spring tube 137within the flexible portion 145 can allow the flexible portion 145 tospring back to its default straightened configuration. Moreover, theflexible portion 145 can bend without adversely affecting the test rod133 within the spring tube 137.

The metal detection device 100 can be configured to undertake testing(for example, functionality testing) or re-zeroing even when theflexible portion 145 is bent. For example, the metal detection device100 can be configured to undertake testing or re-zeroing even when theflexible portion 145 is bent between about 1° to about 90° or beyond90°. Heretofore, to the best of applicant's knowledge, no surgical metaldetectors have been designed with a bendable test rod 133 to allow fortesting or re-zeroing when part of the elongated sensing segment of thedevice 100 is bent or curved.

FIGS. 5A-5D also illustrate that the distal sensing portion 136 cancomprise a proximal gradiometer 200 comprising a first proximalmagnetometer 202 and a second proximal magnetometer 204 and a distalgradiometer 206 comprising a first distal magnetometer 208 and a seconddistal magnetometer 210. For the purposes of this disclosure, the termmagnetometer refers to a device or sensor for measuring components of amagnetic field and the term gradiometer refers to a combination of suchdevices or sensors for measuring a gradient of magnetic fieldcomponents.

The first proximal magnetometer 202 and the second proximal magnetometer204 can be mounted or otherwise coupled to a proximal PCB or circuit andthe first distal magnetometer 208 and the second distal magnetometer 210can be mounted or otherwise coupled to a distal PCB or circuit. In thevariation shown in FIGS. 5A-5D and 6A-6B, the first proximalmagnetometer 202 and the second proximal magnetometer 204 can be mountedor otherwise coupled to proximal rigid PCB 161. In this variation, thefirst distal magnetometer 208 and the second distal magnetometer 210 canbe mounted or otherwise coupled to a distal rigid PCB 163.

The proximal rigid PCB 161 can be connected or otherwise coupled to thedistal rigid PCB 163 by a distal flex circuit 155. In other variations,the first distal magnetometer 208 and the second distal magnetometer 210can be mounted or otherwise coupled to a flex circuit.

Although FIGS. 5A-5D illustrate a variation of the device 100 comprisingtwo gradiometers and four magnetometers, it is contemplated by thisdisclosure that the device 100 can comprise three or more gradiometersor only one gradiometer.

The first proximal magnetometer 202 can be positioned distally of thesecond proximal magnetometer 204. The first distal magnetometer 208 canbe positioned distally of the second distal magnetometer 210.

The first proximal magnetometer 202 can be positioned distally in serieswith the second proximal magnetometer 204 such that the first proximalmagnetometer 202 is positioned distally of the second proximalmagnetometer 204 along a longitudinal axis (for example, thelongitudinal axis 104 shown in FIG. 1A). The first distal magnetometer208 can be positioned distally in series with the second distalmagnetometer 210 such that the first distal magnetometer 208 ispositioned distally of the second distal magnetometer 210.

FIG. 5D illustrates that the first proximal magnetometer 202 can beseparated from the second proximal magnetometer 204 by a proximalmagnetometer separation distance 205. In some variations, the proximalmagnetometer separation distance 205 can be between about 4.00 mm and5.00 mm. For example, the proximal magnetometer separation distance 205can be between about 4.50 mm and 4.75 mm.

The first distal magnetometer 208 can be separated from the seconddistal magnetometer 210 by a distal magnetometer separation distance207. In some variations, the distal magnetometer separation distance 207can be between about 4.00 mm and 5.00 mm. For example, the distalmagnetometer separation distance 207 can be between about 4.50 mm and4.75 mm.

The second distal magnetometer 210 can be separated from the firstproximal magnetometer 202 by a gradiometer separation distance 209. Insome variations, the gradiometer separation distance 209 can be betweenabout 18.00 mm and 20.00 mm. For example, the gradiometer separationdistance 209 can be between about 18.50 mm and 18.85 mm.

One technical problem faced by the applicants is how to design asurgical magnetic detector to detect small or diminutive magnetic itemssuch as small surgical needles or pieces of surgical equipment that havebroken off during surgery. One technical solution discovered by theapplicants is the device 100 disclosed herein having magnetometers andgradiometers positioned and spaced according to the dimensions providedheretofore. The applicants discovered that the separation distancesdisclosed herein (e.g., the magnetometer separation distances and/or thegradiometer separation distances) allow the device 100 to moreeffectively detect small needles or other small ferromagnetic sharps oritems.

Moreover, the device 100 disclosed herein having magnetometers andgradiometers positioned and spaced according to the dimensions providedheretofore, as well as the magnetometer orientations, and unique signalcombinations, can all help with sensing objects of interest and helpwith reducing signal size for erroneous signals caused by moving throughnative magnetic field lines in the operating room (e.g., magnetic fieldlines attributed to the earth, the hospital building, medical equipment,etc.)

The distal sensing portion 136 can also comprise an inertial measurementunit (IMU) 159. The IMU 159 can provide up to six degrees of freedom(DoF). The IMU 159 can be a 6-axis IMU comprising a 3-axis accelerometerand a 3-axis gyroscope. The IMU 159 can measure tilt and angular ratesand accelerations in three perpendicular axes. In some variations, theIMU can be a low-power and low-noise 16-bit IMU. For example, the IMU159 can be BMI055, MBI088, or BMI160 IMU provided by Bosch SensortecGmbH.

Data obtained from the IMU 159 can be used as part of any calculationsconcerning a speed and acceleration of the distal sensing portion 136.For example, data obtained from the IMU 159 as well as thepotentiometers can be used to determine whether an operator has jerkedor yanked the distal sensing portion 136. One or more processors of themicrocontroller can be programmed to execute further instructions todisregard a sudden motion of at least one of the distal sensing portion136 and the shaft 131 based on acceleration data obtained from the3-axis accelerometer and rotational data obtained from the 3-axisgyroscope.

In some variations, the IMU 159 can be mounted to the proximal rigid PCB161. In other variations, the IMU 159 can be mounted to the distal rigidPCB 163 or another part of the distal sensing portion 136.

In some variations, data received from the IMU 159 (for example,acceleration data from the 3-axis accelerometer and/or gyroscope datafrom the 3-axis gyroscope) can influence whether the device 100 lowers asensitivity level or detection sensitivity. Lowering the sensitivitylevel or detection sensitivity can involve raising a sensitivity ordetection threshold to avoid false positive signals. For example, whendata received from the IMU 159 indicates that the distal sensing portion136 is experiencing heightened or exaggerated motion (e.g., the operatorrotates the shaft 131 too quickly or squeezes/lets go of the trigger tooquickly), this can create a sharp spike in the magnetic field detected.In these instances, the one or more processors of the microcontroller185 can be programmed to execute instructions to determine that thedistal sensing portion 136 is experiencing heightened or exaggeratedmotion based on data obtained from the IMU 159 (for example, when motiondata obtained from the IMU 159 exceeds a predetermined motion thresholdor motion threshold range), the one or more processors can then beprogrammed to execute further instructions to raise a programmedsensitivity or detection threshold to lower a sensitivity of the device100 in response to the sudden or uncontrolled movement of the distalsensing portion 136. This can be done to forestall or tamper any falsepositive signals.

In certain variations, the one or more processors can also be programmedto execute further instructions to divide signal or data obtained fromthe various magnetometers by a magnitude of the heightened motion signalor a scaled version of the heightened motion signal to reduce thelikelihood of false positive signals created by the heightened motion.This can be considered an instance of motion blocking or scaling downthe detection signal.

FIG. 6A illustrates a side close-up view of one variation of the distalsensing portion 136 with the sensor housing 141 removed. The distalsensing portion 136 can comprise a proximal gradiometer 200 comprising afirst proximal magnetometer 202 and a second proximal magnetometer 204and a distal gradiometer 206 comprising a first distal magnetometer 208and a second distal magnetometer 210.

Although FIGS. 5A-5D and 6A-6B illustrate the device 100 comprising twogradiometers and four magnetometers, it is contemplated by thisdisclosure that the device 100 can comprise three or more gradiometersor six or more magnetometers. In other variations, the device 100 cancomprise only one gradiometer comprising two magnetometers or onegradiometer comprising two magnetometers and an additional magnetometerdisposed distal or proximal to the one gradiometer.

The first proximal magnetometer 202, the second proximal magnetometer204, the first distal magnetometer 208, and the second distalmagnetometer 210 can be two-axis magnetometers, each having an x-axisand a y-axis. For example, each of the first proximal magnetometer 202,the second proximal magnetometer 204, the first distal magnetometer 208,and the second distal magnetometer 210 can have a positive x-axis(+x-axis), a negative x-axis (−x-axis), a positive y-axis (+y-axis), anda negative y-axis (−y-axis). Each of the x-axis and the y-axis can beconsidered a sensitive axis of the magnetometer.

The +x-axis of the first proximal magnetometer 202 can be orientedopposite the +x-axis of the second proximal magnetometer 204. The+y-axis of the first proximal magnetometer 202 can be oriented oppositethe +y-axis of the second proximal magnetometer 204 (see FIGS. 5C and6A).

The −x-axis of the first proximal magnetometer 202 can be orientedopposite the −x-axis of the second proximal magnetometer 204. The−y-axis of the first proximal magnetometer 202 can be oriented oppositethe −y-axis of the second proximal magnetometer 204.

The sensitive axes (e.g., the x-axis and the y-axis) of the firstproximal magnetometer 202 and the second proximal magnetometer 204 canbe pointed in opposite directions to cancel out or reduce commonmagnetic field influences (e.g., the earth's magnetic field, magneticfield influences from medical equipment in the operating room, or fieldinfluences as a result of motion) such that local magnetic fielddistortions or influences are more pronounced or detectable and a largerpart of the overall signal.

In other variations, only the +x-axis of the first proximal magnetometer202 is oriented opposite the +x-axis of the second proximal magnetometer204 or only the +y-axis of the first proximal magnetometer 202 isoriented opposite the +y-axis of the second proximal magnetometer 204.

The +x-axis of the first distal magnetometer 208 can be orientedopposite the +x-axis of the second distal magnetometer 210 and the+y-axis of the first distal magnetometer 208 can be oriented oppositethe +y-axis of the second distal magnetometer 210 (see FIGS. 6A and 6B).

In other variations, only the +x-axis of the first distal magnetometer208 is oriented opposite the +x-axis of the second distal magnetometer210 or only the +y-axis of the first distal magnetometer 208 is orientedopposite the +y-axis of the second distal magnetometer 210.

The sensitive axes (e.g., the x-axis and the y-axis) of the first distalmagnetometer 208 and the second distal magnetometer 210 can be pointedin opposite directions to cancel out common magnetic field influences(e.g., the earth's magnetic field) such that local magnetic fielddistortions or influences are more pronounced or detectable.

Although reference is made to each of the magnetometers or magneticsensors comprising an x-axis (e.g., +x-axis) and a y-axis (e.g.,+y-axis), it is contemplated by this disclosure that any reference to ax-axis (e.g., +x-axis) or a y-axis (e.g., +y-axis) can also refer to asingle-axis magnetometer where the magnetometer or magnetic sensor onlyhas an x-axis or y-axis. Therefore, any references to four two-axismagnetometers (e.g., a first proximal magnetometer 202, a secondproximal magnetometer 204, a first distal magnetometer 208, and a seconddistal magnetometer 210) can also be applied to eight one-axismagnetometers (e.g., a first proximal magnetometer, a second proximalmagnetometer, a third proximal magnetometer, a fourth proximalmagnetometer, a first distal magnetometer, a second distal magnetometer,a third distal magnetometer, and a fourth distal magnetometer). In someimplementations, the distal sensing portion 136 can comprise fourgradiometers with each gradiometer having two one-axis magnetometers.

In some variations, certain common magnetic field measurements obtainedfrom the proximal gradiometer 200 (the first proximal magnetometer 202,the second proximal magnetometer 204, or a combination thereof) and thedistal gradiometer 206 (the first distal magnetometer 208, the seconddistal magnetometer 210, or a combination thereof) can be canceled outor reduced in order to magnify or make more pronounced local magneticfield distortions or influences caused by RSIs or other ferromagneticobjects. For example, by canceling out common signals or common magneticfield influences (e.g., the earth's magnetic field or magnetic fielddistortions caused by surrounding ferromagnetic hospital equipment),local magnetic field distortions caused by an RSI or other ferromagneticobject closer to one gradiometer can cause a bigger signal at the closergradiometer than the other gradiometer positioned farther away.

As will be discussed in more detail in the following sections, the oneor more processors of the microcontroller 185 can be programmed toexecute instructions stored in the memory units to calculate adifferential signal from magnetic field measurements obtained from thefirst proximal magnetometer 202, the second proximal magnetometer 204,the first distal magnetometer 208, and the second distal magnetometer210.

The distal sensing portion 136 can also comprise one or more operationalamplifiers to amplify raw output signals from at least one of the firstproximal magnetometer 202, the second proximal magnetometer 204, thefirst distal magnetometer 208, and the second distal magnetometer 210.The operational amplifiers can amplify the raw output signals from themagnetometers before such signals are transmitted to the ADC 186 or anADC component of the microcontroller 185 within the handle 102. In somevariations, the one or more operational amplifiers can be mounted to anunderside of the PCBs within the distal sensing portion 136. Forexample, a first proximal operational amplifier and a second proximaloperational amplifier can be mounted to an underside of the proximalrigid PCB 161 to amplify signals from the first proximal magnetometer202 and the second proximal magnetometer 204, respectively. Also, forexample, a first distal operational amplifier and a second distaloperational amplifier can be mounted to an underside of the distal rigidPCB 163 to amplify signals from the first distal magnetometer 208 andthe second distal magnetometer 210, respectively (see, for example,FIGS. 7A-7C).

At least one of the first proximal magnetometer 202, the second proximalmagnetometer 204, the first distal magnetometer 208, and the seconddistal magnetometer 210 can be an anisotropic magnetoresistance (AMR)sensor. For example, at least one of the first proximal magnetometer202, the second proximal magnetometer 204, the first distal magnetometer208, and the second distal magnetometer 210 can be a two-axis AMRsensor. At least one of the first proximal magnetometer 202, the secondproximal magnetometer 204, the first distal magnetometer 208, and thesecond distal magnetometer 210 can be a solid-state AMR sensor designedfor low-field magnetic sensing.

As s more specific example, at least one of the first proximalmagnetometer 202, the second proximal magnetometer 204, the first distalmagnetometer 208, and the second distal magnetometer 210 can be an HMC1052 AMR sensor (Part No. HMC1052L-TR) distributed by HoneywellInternational Inc.

In other variations, at least one of the first proximal magnetometer202, the second proximal magnetometer 204, the first distal magnetometer208, and the second distal magnetometer 210 can be a three-axis AMRsensor.

AMR sensors can make use of a magneto-resistive material (e.g.,permalloy) to act as a magnetometer. Permalloy is an alloy containingroughly 80% nickel and 20% iron. The alloy's resistance depends on theangle between the metallization and the direction of current flow. In amagnetic field, magnetization rotates toward the direction of themagnetic field and the rotation angle depends on the external field'smagnitude. For example, the AMR sensors can include thin strips ofpermalloy (e.g., NiFe magnetic film) whose electrical resistance varieswith a change in the magnetic field.

In some variations, the magnetometers can be any type ofmagneto-resistive sensor that provides a change in resistance inresponse to a change in a magnetic field along a given axis. In othervariations, the magnetometers can be any type of vector magnetometer formeasuring the vector components of a magnetic field.

The magnetometers (any one of the first proximal magnetometer 202, thesecond proximal magnetometer 204, the first distal magnetometer 208, andthe second distal magnetometer 210) can comprise a communicationinterface that can transmit magnetic field measurements using acommunication protocol. The magnetometers can operate with a low voltagepower supply such as, for example, a power supply providing voltage lessthan about 2.0 V, 2.5V, 3.0V, 3.5V, 4.0V, 4.5V, 5.0V, 5.5V, or 6.0V. Themagnetometers can be designed to be surface mounted to the PCBs of thedistal sensing portion 136. For example, the first proximal magnetometer202 and the second proximal magnetometer 204 can be surface mounted tothe proximal rigid PCB 161 and the first distal magnetometer 208 and thesecond distal magnetometer 210 can be surface mounted to the distalrigid PCB 163.

FIG. 6A also illustrates that the device 100 can comprise a distal LED183. The distal LED 183 can be mounted to a distal end of the elongateflex circuit 157 near the proximal rigid PCB 161. In other variations,the distal LED 183 can be mounted to the proximal rigid PCB 161, thedistal flex circuit 155, or the distal rigid PCB 163.

The sensor housing 141 (see, for example, FIGS. 1A, 1B, 3A, 3B, and 7C)can comprise a light transmittance window or a light transmittingportion to allow light generated by the distal LED 183 to be madevisible to an operator via endoscopy.

The distal LED 183 can function similar to the proximal LED 173. Thesame light or light patterns generated by the distal LED 183 can also begenerated by the proximal LED 173 (and vice versa). The light or lightpatterns generated by the distal LED 183 and/or the proximal LED 173 canconvey information concerning a battery life of the device 100, astandby indication, an error warning, a detection status, or acombination thereof.

FIGS. 5A-5D and 6A-6B also illustrate that the distal rigid PCB 163 canbe angularly rotated with respect to the proximal rigid PCB 161. Thedistal rigid PCB 163 can be maintained in this rotated or twistedconfiguration with respect to the proximal rigid PCB 161.

For example, the distal rigid PCB 163 can be maintained in this rotatedor twisted configuration by the sensor housing 141 (not shown in FIG. 6Afor ease of viewing). Also, for example, the distal rigid PCB 163 can bemaintained in this rotated or twisted configuration by one or morefixation components such as one or more clips, clasps, space fillers, ora combination thereof.

The distal rigid PCB 163 can be rotated by a twist angle 220. In somevariations, the twist angle 220 can be about 45 degrees.

In other variations, the twist angle 220 can be about 60 degrees,between about 45 degrees and 60 degrees, or less than about 45 degrees.In certain variations, the twist angle 220 can be about 30 degrees.

In some variations, the twist angle 220 can refer to an angle ofrotation of at least one of the second distal magnetometer 210 and thefirst distal magnetometer 208 with respect to the first proximalmagnetometer 202.

The distal rigid PCB 163 can be rotated about the distal flex circuit155 connecting the proximal rigid PCB 161 to the distal rigid PCB 163.While FIGS. 5A-5D and 6A-6B illustrate the distal rigid PCB 163 rotatedin a counterclockwise rotational direction when viewed from a proximalend of the distal sensing portion 136 to a distal end of the distalsensing portion 136, it is contemplated by this disclosure that thedistal rigid PCB 163 can also be rotated in a clockwise rotationaldirection when viewed from the proximal end of the distal sensingportion 136 to the distal end of the distal sensing portion 136.

In some variations, one of the axes of the magnetometers on the distalrigid PCB 163 can be aligned with one of the axes of the magnetometerson the proximal rigid PCB 161. For example, each of the x-axes of thefirst distal magnetometer 208 and the second distal magnetometer 210 canbe axially aligned with or positioned along the same axial plane as thex-axes of the first proximal magnetometer 202 and the second proximalmagnetometer 204. In these variations, the other axis of themagnetometers on the distal rigid PCB 163 can be out of alignment withthe other axis of the magnetometers on the proximal rigid PCB 161. Forexample, each of the y-axes of the first distal magnetometer 208 and thesecond distal magnetometer 210 can be out of alignment or rotated (forexample, by the twist angle 220) with respect to the y-axes of the firstproximal magnetometer 202 and the second proximal magnetometer 204.

Although FIGS. 6A and 6B illustrate the x-axes of the magnetometers asbeing axially aligned or in planar alignment and the y-axes being out ofalignment, it is contemplated by this disclosure that the y-axes of themagnetometers can be axially aligned or in planar alignment and thex-axes can be out of alignment.

Twisting, contorting, or otherwise rotating the distal rigid PCB 163with respect to the proximal rigid PCB 161 can allow the magnetometersof the distal gradiometer 206 to provide magnetic field measurements inat least one additional axis. For example, when the magnetometers of thedistal gradiometer 206 are two-axis magnetometers (for example,magnetometers have an x-axis and a y-axis), twisting, contorting, orotherwise rotating the distal rigid PCB 163 can allow the magnetometersof the distal gradiometer 206 to provide magnetic field measurements ina third axis when one of the axes of the magnetometers on the distalrigid PCB 163 are axially aligned or in planar alignment with the sameaxis on the proximal rigid PCB 161 (for example, when the x-axes aresubstantially axially aligned or positioned along the same axial planeas the x-axes on the other board). In this example, the y-axes of themagnetometers on the distal rigid PCB 163 would provide additionalmagnetic field measurements in a third axis.

In addition, although FIGS. 5A-5D and 6A-6B illustrate the distal rigidPCB 163 as being twisted, contorted, or otherwise rotated, it iscontemplated by this disclosure that the proximal rigid PCB 161 can betwisted, contorted, or otherwise rotated.

One technical advantage of twisting, contorting, or otherwise rotatingone of the gradiometer circuit boards with respect to the othergradiometer circuit board (e.g., the distal rigid PCB 163 with respectto the proximal rigid PCB 161) is to allow the applicant to use smallerand cheaper two-axis magnetometers for sensing rather than having torely on expensive and bulkier three-axis magnetometers. As previouslydiscussed, twisting, contorting, or otherwise rotating one of thegradiometer circuit boards can allow the magnetometers on the twisted orrotated board to be used as pseudo “three-axis magnetometers” such thatthe magnetometers provide magnetic field measurements in an additionalaxis. In this manner, the twist or rotation can allow the applicant toachieve three-dimensional detection sensitivity with two-dimensionalsensors.

For example, FIG. 6B illustrates that when the distal rigid PCB 163 istwisted or rotated, the y-axes of the first distal magnetometer 208 andthe second distal magnetometer (now referred to as Y1′ and Y2′,respectively) can be broken up into y-vector components (Y1 and Y2,respectively) substantially aligned with the y-axes of the firstproximal magnetometer 202 and the second proximal magnetometer 204 andnew z-vector components (Z1 and Z2, respectively) that have noequivalents on the proximal gradiometer 200. The new z-vector componentscan act as a pseudo third axis such that additional magnetic fieldmeasurements can be obtained along this additional axis.

Another technical advantage of twisting, contorting, or otherwiserotating one of the gradiometer circuit boards with respect to the othergradiometer circuit board (e.g., the distal rigid PCB 163 with respectto the proximal rigid PCB 161) is that differentials or comparisons ofmagnetic field values can be taken from magnetometer-pairs on the samegradiometer board but also from magnetometers on different gradiometerboards. These differentials or comparisons can be used to cancel out orreduce common magnetic field influences in order to magnify or make morepronounced local magnetic field distortions or influences caused by RSIsor other ferromagnetic objects.

FIGS. 7A and 7B illustrate isometric views of another variation of thedistal sensing portion 136 of the metal detection device with the sensorhousing 141 removed. In this variation, the distal rigid PCB 163, thedistal flex circuit 155, and the proximal rigid PCB 161 can be replacedby a singular rigid PCB 187. Also, in this variation, the magnetometersof the distal gradiometer 206 are not rotated with respect to themagnetometers of the proximal gradiometer 200.

As illustrated in FIGS. 7A and 7B, axes of the first proximalmagnetometer 202 and the second proximal magnetometer 204 are eitheraligned or orthogonal to axes of the first distal magnetometer 208 andthe second distal magnetometer 210. For example, the x-axes of the firstdistal magnetometer 208 and the second distal magnetometer 210 can beaxially aligned with or positioned along the same axial plane as thex-axes of the first proximal magnetometer 202 and the second proximalmagnetometer 204. Also, for example, the y-axes of the first distalmagnetometer 208 and the second distal magnetometer 210 can beorthogonal to the x-axes of the first proximal magnetometer 202, thesecond proximal magnetometer 204, the first distal magnetometer 208, andthe second distal magnetometer 210.

Although FIGS. 7A and 7B illustrate the circuit board of the distalsensing portion 136 as a singular rigid PCB 187, it is contemplated bythis disclosure that the singular rigid PCB can also be implemented astwo rigid PCBs connected by a flexible circuit. In this variation, afixation component.

The +x-axis of the first proximal magnetometer 202 can be orientedopposite the +x-axis of the second proximal magnetometer 204. The+y-axis of the first proximal magnetometer 202 can be oriented oppositethe +y-axis of the second proximal magnetometer 204.

The +x-axis of the first distal magnetometer 208 can be orientedopposite the +x-axis of the second distal magnetometer 210 and the+y-axis of the first distal magnetometer 208 can be oriented oppositethe +y-axis of the second distal magnetometer 210.

In some variations, the +x-axis of the second distal magnetometer 210can be oriented opposite the +x-axis of the first proximal magnetometer202. In these and other variations, the +y-axis of the second distalmagnetometer 210 can be oriented opposite the +y-axis of the firstproximal magnetometer 202.

FIG. 7B is the same figure as FIG. 7A except the +x-axes and the +y-axesare now replaced with labels to represent measurements obtained by themagnetometers along such axes. Magnetic field measurements obtainedalong the positive x-axis of the first distal magnetometer 208 is nowreferred to as X1, the positive y-axis of the first distal magnetometer208 is now referred to as Y1, the positive x-axis of the second distalmagnetometer 210 is now referred to as X2, the positive y-axis of thesecond distal magnetometer 210 is now referred to as Y2, the positivex-axis of the first proximal magnetometer 202 is now referred to as X3,the positive y-axis of the first proximal magnetometer 202 is nowreferred to as Y3, the positive x-axis of the second proximalmagnetometer 204 is now referred to as X4, and the positive y-axis ofthe second proximal magnetometer 204 is now referred to as Y4.

Equations 1-17 below are equations devised by the applicant to calculatea differential signal from magnetic field measurements obtained from thefirst proximal magnetometer 202, the second proximal magnetometer 204,the first distal magnetometer 208, and the second distal magnetometer210. The one or more processors of the microcontroller 185 can beprogrammed to execute instructions to calculate the differential signalusing any of the equations below.

(X1+X2)−(X3+X4)+((Y1+Y2)−(Y3+Y4))=X1+X2−X3−X4+Y1+Y2−Y3−Y4  Equation 1(also referred to as an on-axis local differential signal)

(X1+X4)−(X3+X2)+((Y1+Y4)−(Y3+Y2))=X1−X2−X3+X4+Y1−Y2−Y3+Y4  Equation 2(also referred to as an on-axis global differential signal)

(X1+X2)−(X3+X4)+((Y1−Y2)−(Y3−Y4))=X1+X2−X3−X4+Y1−Y2−Y3+Y4  Equation 3(also referred to as an on-axis Y local differential signal)

(X1+X4)−(X3+X2)+((Y1−Y4)−(Y3−Y2))=X−X2−X3+X4+Y1+Y2−Y3−Y4  Equation 4(also referred to as an on-axis Y global differential signal)

(X1+X2)−(X3+X4)−((Y1+Y2)−(Y3+Y4))=X1+X2−X3−X4−Y1−Y2+Y3−Y4  Equation 5(also referred to as an on-axis ortho local differential signal)

(X1+X4)−(X3+X2)−((Y1+Y4)−(Y3+Y2))=X1−X2−X3+X4−Y1+Y2+Y3−Y4  Equation 6(also referred to as an on-axis ortho global differential signal)

(X1+Y2)−(X3+Y4)+((Y1+X2)−(Y3+X4))=X1+X2−X3−X4+Y1+Y2−Y3−Y4  Equation 7(also referred to as an off-axis local differential magnetometer signal)

(X1+Y1)−(X2+Y2)+((Y3+X3)−(Y4+X4))=X1−X2+X3−X4+Y1−Y2+Y3−Y4  Equation 8(also referred to as an off-axis super local differential signal)

(X1+Y4)−(X3+Y2)+((Y1+X4)−(Y3+X2))=X1−X2−X3+X4+Y1−Y2−Y3+Y4  Equation 9(also referred to as an off-axis global differential signal)

(X1+Y3)−(X2+Y4)+((Y1+X3)−(Y2+X4))=X1−X2+X3−X4+Y1−Y2+Y3−Y4  Equation 10(also referred to as an off-axis super global differential signal)

(X1+Y2)−(X3+Y4)−((Y1+X2)−(Y3+X4))=X1−X2−X3+X4−Y1+Y2+Y3−Y4  Equation 11(also referred to as an off-axis ortho local differential signal)

(X1+Y4)−(X3+Y2)−((Y1+X4)−(Y3+X2))=X1+X2−X3−X4−Y1−Y2+Y3+Y4  Equation 12(also referred to as an off-axis ortho global differential magnetometersignal)

(X1+Y1)−(X2+Y2)−((Y3+X3)−(Y4+X4))=X1−X2−X3+X4+Y1−Y2−Y3+Y4  Equation 13(also referred to as an off-axis ortho super local differential signal)

(X1+Y3)−(X2+Y4)−((Y1+X3)−(Y2+X4))=X1−X2−X3+X4−Y1+Y2+Y3−Y4  Equation 14(also referred to as off-axis ortho super global differential signal)

(X1−X2)−(X3−X4)+((Y1−Y2)−(Y3−Y4))=X1−X2−X3+X4+Y1−Y2−Y3+Y4  Equation 15(also referred to as full global differential magnetometer signal)

(X1−X2)−(X3−X4)−((Y1−Y2)−(Y3−Y4))=X1−X2−X3+X4−Y1+Y2+Y3−Y4  Equation 16(also referred to as full global ortho differential signal)

(−X1+X2)−(−X3+X4)+((−Y1+Y2)−(−Y3+Y4))=−X1+X2+X3−X4−Y1+Y2+Y3−Y4  Equation17 (also referred to as inverse full global differential signal)

abs(X1−X1zero)+abs(X2−X2zero)+abs(X3−X3zero)+abs(X4−X4zero)+abs(Y1−Y1zero)+abs(Y2Y2zero)+abs(Y3−Y3zero)+abs(Y4−Y4zero)  Equation 18 (also referred to asa zeroed-sum signal or a “soup” signal)

As shown above, Equations 2, 9, 13, and 15 produced the same finalresult despite the initial groupings being different. Moreover,equations 1 and 7 also produced the same net result.

Equation 18 is a zeroed sum (meaning the first reading or referencereading is subtracted from the signal going forward) of the absolutevalue of all of the magnetometers that were investigated as a potentialhigh sensitivity candidate signal. The signal obtained from Equation 18is also referred to as a “soup” signal. Since it does not have theadvantage of subtracting common signals created from moving throughearth's magnetic field lines this signal is much more susceptible tosignals caused by moving through magnetic field lines in the room thanEquations 2 or 6 which can have up to 4-5 times better needle detectionto motion signal ratios.

One advantage of calculating the differential signal using the equationsdisclosed herein is that common magnetic field influences (e.g., theearth's magnetic field, magnetic field influences from medical equipmentin the operating room, or field influences as a result of motion) arecanceled out or reduced and local magnetic field distortions orinfluences are more noticeable and become a larger part of the overallsignal.

It should be noted that the positive and negative signs in theaforementioned equations take into account that the magnetometers of thedevice 100 are configured in the manner shown in FIGS. 7A and 7B. Forexample, adding X1 and X2 is actually subtracting the two signals andsubtracting X1 from X2 is actually adding the two signals.

In some circumstances, the differential signal calculated usingequations 2, 9, 13, and 15 can be more pronounced or noticeable than thesignals calculated using the other equations. In other circumstances,the differential signal calculated using equation 6 can be morepronounced or noticeable than the signals calculated using the otherequations. Moreover, the differential signal calculated using equations2, 9, 13, and 15 demonstrated nice cancellations of signals caused bymoving through magnetic field lines in the operating room compared tomore localized magnetic field distortions attributed to small stainlesssteel RSIs or other ferromagnetic objects.

The one or more processors of the microcontroller 185 can be programmedto execute further instructions to calculate the differential signalusing more than one of the aforementioned equations and to switchbetween or cycle through different equations. For example, the one ormore processors of the microcontroller 185 can be programmed to executefurther instructions to calculate the differential signal using Equation2 (the on-axis global differential signal) as well as Equations 3 (theon-axis Y local differential signal), 5 (the on-axis ortho localdifferential signal), and 6 (the on-axis ortho global differentialsignal).

Although reference is made above to each of the magnetometers ormagnetic sensors comprising an x-axis (e.g., +x-axis) and a y-axis(e.g., +y-axis), it is contemplated by this disclosure that anyreference to a x-axis (e.g., +x-axis) or a y-axis (e.g., +y-axis) canalso refer to a single-axis magnetometer where the magnetometer ormagnetic sensor only has an x-axis or y-axis. Therefore, any referencesto four two-axis magnetometers (e.g., a first proximal magnetometer 202,a second proximal magnetometer 204, a first distal magnetometer 208, anda second distal magnetometer 210) can also be applied to eight one-axismagnetometers (e.g., a first proximal magnetometer, a second proximalmagnetometer, a third proximal magnetometer, a fourth proximalmagnetometer, a first distal magnetometer, a second distal magnetometer,a third distal magnetometer, and a fourth distal magnetometer). In someimplementations, the distal sensing portion 136 can comprise fourgradiometers with each gradiometer having two one-axis magnetometers.For example, in the equations above, any references to X1, X2, X3, X4,Y1, Y2, Y3, and Y4 can also refer to one axis of each of a firstmagnetometer, a second magnetometer, a third magnetometer, a fourthmagnetometer, a fifth magnetometer, a sixth magnetometer, a seventhmagnetometer, and an either magnetometer, respectively.

A user or operator of the device 100 can also apply a user input (e.g.,dialing the sensitivity wheel(s) 115 forward or backward) to instructthe one or more processors of the microcontroller 185 to switch betweenor cycle through different equations to calculate the differentialsignal.

Referring back to FIG. 6B, below is an additional equation (Equation 19)devised by the applicant to calculate a differential signal frommagnetic field measurements obtained from the first proximalmagnetometer 202, the second proximal magnetometer 204, the first distalmagnetometer 208, and the second distal magnetometer 210 when the distalrigid PCB 163 is twisted or rotated by a twist angle (e.g., 45 degrees):

(X1+X2)−(X3+X4)+(½*Y1+½*Y2)−(Y3+Y4)+(½*Z1+½*Z2)=X1+X2−X3−X4+(½*Y1)+(½*Y2)−Y3−Y4+(½*Z1)+(½*Z2)  Equation19 (also referred to as an on-axis distal twist local differentialsignal)

As will be discussed in more detail in the following sections, the oneor more processors of the microcontroller 185 can be programmed toexecute instructions to calculate the differential signal using any ofthe above equations.

The one or more processors of the microcontroller 185 can be programmedto execute instructions to calculate the differential signal using anycombination of these equations at various points in time or otherequations by themselves or in a sequence to evaluate local magneticfield distortions from different perspectives over time. At high speedthese various perspectives can be combined to form an ensemble signalduring use as small field distortions pass by the device.

The one or more processors of the microcontroller 185 can be programmedto execute further instructions to apply one or more filters (e.g., ahigh-pass filter and/or a low-pass filter) to the differential signal toobtain a detection signal. A smoothing function can also be applied tothe detection signal.

In other variations, the one or more processors of the microcontroller185 can be programmed to execute instructions to take the derivative orapply a derivative function to or take the derivative of thedifferential signal to obtain the detection signal.

The one or more processors of the microcontroller 185 can be programmedto execute further instructions to compare the detection signal againsta sensitivity or detection threshold. The output component (e.g.,speaker and/or LED(s)) can then be instructed to generate a user output(e.g., a beeping sound and/or a bright light) when the detection signalexceeds a sensitivity or detection threshold.

In some variations, whether a signal filter is applied or whether aderivative is taken is determined based on a sensitivity level set bythe operator of the device 100 (e.g., surgeon or another medicalprofessional). For example, the operator can dial the sensitivitywheel(s) 115 forward or in a distal direction until the sensitivitylevel or detection sensitivity of the device is at level 8 or above.When the sensitivity level is at a level 8 or higher, the one or moreprocessors of the microcontroller 185 can be programmed to executeinstructions to apply one or more filters to the differential signal toobtain the detection signal but not take the derivative.

In another scenario, the operator can dial the sensitivity wheel(s) 115backward or in a proximal direction until the sensitivity level ordetection sensitivity of the device 100 is at level 7 or below. When thesensitivity level is at a level 7 or lower, the one or more processorsof the microcontroller 185 can be programmed to execute instructions totake the derivative and apply one or more motion blocking algorithms toobtain the detection signal.

In any case, the detection signal is compared against a sensitivity ordetection threshold and the output component(s) are instructed togenerate the user output when the detection signal exceeds thesensitivity or detection threshold.

As shown in FIGS. 7A and 7B, the distal sensing portion 136 can furthercomprise one or more operational amplifiers coupled to the rigid PCB187. The one or more operational amplifiers can be configured to amplifyraw output signals from the various magnetometers before such signalsare transmitted to the ADC 186 or an ADC component of themicrocontroller 185 within the handle 102. For example, the operationalamplifiers can comprise a first proximal operational amplifier 212, asecond proximal operational amplifier 214, a first distal operationalamplifier 216, and a second distal operational amplifier 218. The firstproximal operational amplifier 212 can amplify a raw output signal ofthe first proximal magnetometer 202. The second proximal operationalamplifier 214 can amplify a raw output signal of the second proximalmagnetometer 204. The first distal operational amplifier 216 can amplifya raw output signal of the first distal magnetometer 208. The seconddistal operational amplifier 218 can amplify a raw output signal of thesecond distal magnetometer 210.

The first proximal operational amplifier 212 can be mounted on anunderside of the circuit board (for example, the rigid PCB 187 or theproximal rigid PCB 161) carrying the first proximal magnetometer 202.The second proximal operational amplifier 214 can be mounted on anunderside of the circuit board (for example, the rigid PCB 187 or theproximal rigid PCB 161) carrying the second proximal magnetometer 204.The first distal operational amplifier 216 can be mounted on anunderside of the circuit board (for example, the rigid PCB 187 or thedistal rigid PCB 163) carrying the first distal magnetometer 208. Thesecond distal operational amplifier 218 can be mounted on an undersideof the circuit board (for example, the rigid PCB 187 or the distal rigidPCB 163) carrying the second distal magnetometer 210.

In other variations, the operational amplifiers (e.g., the firstproximal operational amplifier 212, the second proximal operationalamplifier 214, the first distal operational amplifier 216, the seconddistal operational amplifier 218, or a combination thereof) can bemounted to the handle PCB 123 or a circuit board housed in anotherportion of the device 100.

FIG. 7C illustrates a sensor housing 141 covering the distal sensingportion 136. As previously discussed, the sensor housing 141 can have ahousing diameter 138 (see FIGS. 3A and 3B). The housing diameter 138 canbe between about 3.0 mm to about 10.0 mm (e.g., about 5.0 mm).

FIG. 7C also illustrates that a fixation component 188 within the sensorhousing 141 can secure the electronic components within the sensorhousing 141 such that the electronic components (e.g., the magnetometersor op amps) do not become uncoupled or detached when the distal sensingportion 136 is bent toward the shaft or the shaft 131 is rotated.

In some variations, the fixation component 188 can be a polymeric holderor clip. In other variations, the fixation component 188 can be a claspor other type of space filler.

As previously discussed, when the distal rigid PCB 163 is rotated,contorted, or otherwise rotated with respect to the proximal rigid PCB161, another instance of the fixation component 188 can also be used tomaintain the distal rigid PCB 163 in its rotated, contorted, orotherwise rotated configuration.

FIGS. 8A and 8B illustrate rear close-up isometric views of the clockingring 107 in a locked position 108 and an unlocked position 110,respectively. The left handle casing 101 is removed in FIGS. 8A-8B tobetter illustrate components within the handle 102. FIGS. 8A-8Billustrate that the shaft can be coupled to a tube boss 113 positionedwithin the handle 102. The clocking ring 107 can be rotationally fixedto the tube boss 113 such that rotation of the clocking ring 107 canrotate the tube boss 113 and, thereby, the shaft 131. The clocking ringcan be defined by grooves or furrows to allow an operator to more easilytranslate and rotate the clocking ring 107.

The locking ring 111 can be translationally and rotationally fixed tothe left handle casing 101 and the right handle casing 103 via snapclips or other fasteners. The locking ring 111 can comprise a pluralityof locking splines 175 defined around the circumference of the lockingring 111. The clocking ring 107 can comprise a plurality of reciprocallocking splines 174 for engaging with the locking splines 175 on thelocking ring 111.

As shown in FIG. 8A, the clocking ring 107 can be positioned over thelocking ring 111 when the clocking ring 107 is in a locked position 108.The locking splines 175 on the locking ring 111 can interlock with thereciprocal locking splines 174 of the clocking ring 107 to inhibitrotation of the clocking ring 107.

The clocking ring 107 can be pushed or slid distally forward into anunlocked position 110. The clocking ring 107 can be pushed or sliddistally in a direction of the shaft 131 as shown by the enlarged arrowin FIG. 8A. For example, an operator (e.g., a surgeon or other medicalprofessional) can hold the handle 102 with one hand and push or slidethe clocking ring 107 forward with the other hand.

FIG. 8B illustrates that the reciprocal locking splines 174 of theclocking ring 107 can be disengaged from the locking splines 175 of thelocking ring 111 when the clocking ring 107 is in the unlocked position110. The clocking ring 107 can be rotated, in a clockwise direction orcounterclockwise direction, when in the unlocked position 110. Rotatingthe clocking ring can rotate the tube boss 113 and the shaft 131 (aswell as the flexible portion 145 and the distal sensing portion 136).

Once the operator has rotated the clocking ring 107 to the desiredrotational position, the operator can pull or slide the clocking ring107 back onto the locking ring 111 to lock the clocking ring 107 inplace. The operator can pull or slide the clocking ring 107 back ontothe locking ring 111 in a direction of the handle proximal end as shownby the enlarged arrow in FIG. 8B. The operator can continue to unlockand lock the clocking ring 107 to achieve a desired rotation of theshaft 131.

The operator can rotate the clocking ring 107 while simultaneouslysqueezing the trigger 105 to bend the flexible portion 145. The abilityto rotate the shaft 131 while also bending the flexible portion 145 canallow an operator to probe various body cavities or lumens and sweepbehind or around organs with minimal movement of the user's hands. Onetechnical advantage of the device 100 is the multiple degrees of freedomafforded by the control mechanism disclosed herein.

FIG. 8C illustrates a close-up side view of the clocking ring 107 in thelocked position and FIG. 8D illustrates a sectional view of the clockingring 107 in the locked position 108 along section C-C shown in FIG. 8C.FIG. 8E illustrates a close-up side view of the clocking ring 107 in theunlocked position 110 and FIG. 8F illustrates a sectional view of theclocking ring 107 in the unlocked position 110 along section D-D shownin FIG. 8E. The spring tube 137, test rod 133, and flexible circuitswithin the shaft 131 are not shown in FIGS. 8C-8F for ease of viewing.

FIGS. 8C-8F illustrate that a nose cap 109 can be coupled to the tubeboss 113 within the handle 102 via snap clips or other fasteners. Theouter surface of the nose cap 109 can serve as a bearing surface orreceiving surface for the clocking ring 107 as the clocking ring 107 ispushed distally or pulled proximally. The nose cap 109 can also serve asa bearing surface for the clocking ring 107 as the clocking ring 107 isrotated by the operator.

FIGS. 8D and 8F also illustrate that a shaft locking boss 177 can extendfrom a radially inner surface of the tube boss 113 into a mating hole onthe shaft 131. This can allow the tube boss 113 to be rotationally andtranslationally coupled to the shaft 131.

FIGS. 8G and 8H illustrate front close-up isometric views of theclocking ring 107 in the locked position 108 and the unlocked position110, respectively, with the nose cap 109 removed for use of viewing.FIGS. 8G and 8H illustrate that a distal end 112 of the tube boss 113can comprise a polygonal feature, such as a substantially square-shapedblock, that can mate with a square-shaped cutout (or anotherpolygonal-shaped cutout) in the clocking ring 107 in order torotationally couple the clocking ring 107 to the tube boss 113.

The tube boss 113 can comprise a number of clocking ring detents 179that can interfere with reciprocal features on an inner surface of theclocking ring 107. The clocking ring detents 179 can prevent theclocking ring 107 from translating distally (i.e., from being unlocked)without sufficient force applied by an operator (e.g., a surgeon orother medical professional). Once sufficient distal force is applied tothe clocking ring 107, the clocking ring detents 179 can deform ordeflect and allow the clocking ring 107 to translate distally (as shownby the enlarged arrow in FIG. 8G) and become free to rotate.

FIG. 8H illustrates that the clocking ring 107, in its unlocked position110, can be rotated in a clockwise or counterclockwise rotationaldirection. When the clocking ring 107 is in the unlocked position 110,the clocking ring detents 179 can be positioned behind or proximal tothe interfering features on the clocking ring 107. When the operatordesires to lock the shaft 131 into place, the operator can applysufficient force to pull the clocking ring 107 backward or proximally ina direction of the enlarged arrow (e.g., in a direction of the handleproximal end) such that the clocking ring detents 179 once again engageswith the interfering features on the clocking ring 107.

FIG. 9A is an image of the metal detection device 100 used to detect asurgical needle 900 within a body cavity of a subject. FIG. 9B is animage of forceps 902 used to retrieve the surgical needle 900 upondetection by the metal detection device 100. FIGS. 9A and 9B illustratethat upon detection by the device 100, forceps 902 or other surgicalgraspers can be used to retrieve the surgical needle 900 (or other RSI)from the body of the subject.

In other variations not shown in the figures, the device 100 cancomprise one or more permanent magnets, electromagnets, or a combinationthereof. The one or more permanent magnets, electromagnets, or acombination thereof can be positioned within the distal sensing portion136. The one or more permanent magnets, electromagnets, or a combinationthereof can be positioned along a segment of the shaft 131. In thesevariations, detection of the RSI or ferromagnetic object can beconducted with the electromagnet powered off or demagnetized. Once theRSI or other ferromagnetic objected is detected by the device 100, anoperator can turn on or magnetize the electromagnet and use theelectromagnet and/or permanent magnet to magnetically attract the RSI orferromagnetic object.

The electromagnet can have a variable field strength. In somevariations, an operator can adjust the field strength of theelectromagnet between one or more strength levels based on the size ormagnetism of the RSI or ferromagnetic object.

FIG. 10A illustrates that the metal detection device 100 disclosedherein can also be used to undertake intracorporeal detection ofsurgical sponges 300 including RFID-tagged sponges 302 andmetallic-marked sponges 304 tagged with one or more metallic markers306. Surgical sponges 300 often rank highest among all RSIs. In onestudy, sponge products accounted for 68% of all RSIs. See Cima, RobertR., et al. “Using a data-matrix-coded sponge counting system across asurgical practice: impact after 18 months.” The Joint Commission Journalon Quality and Patient Safety 37.2 (2011): 51-AP3.

The metallic-marked sponges 304 can be tagged or otherwise embedded withone or more ferromagnetic metallic markers 306 or ferromagnetic metallictags. For example, the metallic-marked sponges 304 can compriseferromagnetic beads, wires, threads, or a combination hereof embedded orinterwoven with fabric or other material making up at least part of thesponge.

The RFID-tagged sponges 302 can comprise an RFID tag 308 embedded withinone or more layers of the sponge. The RFID tag 308 can be a passive RFIDtransponder. In other variations, the RFID tag 308 can be an active RFIDtransponder having its own power source.

As shown in FIG. 10A, the device 100 can comprise an RFID reader 310within the distal sensing portion 136. The distal sensing portion 136can comprise the various magnetometers and other electronic componentsdisclosed herein in addition to the RFID reader 310. The RFID reader 310can be configured to read one or more RFID tags 308 within theRFID-tagged sponges 302. The RFID reader 310 can be electrically coupledto or be in electrical communication with the microcontroller 185 suchthat the microcontroller 185 can instruct the RFID reader 310 totransmit an interrogating pulse to the RFID tag(s) 308 to obtainidentifying information or data concerning the RFID-tagged sponges 302.

The RFID reader 310 can allow the device 100 to account for missing orretained RFID-tagged sponges 302 and to locate such RFID-tagged sponges302 intraoperatively within a body cavity of the patient.

In these and other variations, the device 100 can also be used to locatemisplaced or retained metallic-marked sponges 304 using themagnetometers and magnetic detection algorithms disclosed herein. Forexample, an operator or medical professional can adjust the sensitivityof the device 100 using the sensitivity wheel(s) 115 until the device100 generates a user output to indicate the presence of ametallic-marked sponge 304 within a body cavity of the patient.

FIG. 10B illustrates that the metal detection device 100 disclosedherein can also be used to undertake intracorporeal detection offerromagnetic wires 312 such as surgical wires, guidewires,intravascular wires, or a combination thereof. In these and othervariations, the device 100 can also be used to locate or detectferromagnetic catheters, sheaths, tubes, clips, other medicalinstruments, or fragments/segments thereof.

Moreover, the metal detection device 100 disclosed herein can also beused to undertake intracorporeal detection of non-ferromagnetic wires,catheters, sheaths, tubes, clips, or other medical instruments that havebeen tagged with a ferromagnetic tag or plate.

FIG. 11A illustrates another variation of the metal detection device 100comprising a linking cable 314 extending from the device 100 (e.g., aproximal end or handle 102 of the device 100) and electrically coupledto a closed-circuit indicator 318 disposed outside of the body of thepatient. A proximal end of a wire 312, such as a ferromagnetic guidewireor surgical wire, can be extended outside or otherwise exit the body ofthe patient and be electrically coupled to the closed-circuit indicator318. The distal end of the wire or a segment of the wire 312 can bewithin the body of the patient. As shown in FIG. 11A, the device 100 cancomprise a conductive element 316, such as a conductive patch, at adistal end of the device 100. For example, the conductive element 316can extend from the distal sensing portion 136 out of the sensor housing141 or be disposed along the shaft 131. The conductive element 316 canbe in electrically coupled to or be in electrical communication with thelinking cable 314.

When the conductive element 316 makes contact with the wire 312 withinthe body of the patient, the closed-circuit indicator 318 can generate asignal or output (e.g., a sound or auditory instruction, a light orlight pattern, or a combination thereof) to indicate that a closedcircuit is achieved by the conductive element 316 making contact withthe wire 312 within the body of the patient. This mechanism can be usedto detect the location of the wire 312 within the patient. This isespecially important when the wire 312 is not visible to a surgeon orother medical professional directly or via endoscopy.

FIG. 11B illustrates that the metal detection device 100 disclosedherein can also be used to undertake intracorporeal detection offerromagnetic stents 320 or other supporting scaffolds. The device 100can be used to detect or verify an implantation site of the stent 320 orsupporting scaffold. The device 100 can also be used to detect anon-ferromagnetic stent 320 or supporting scaffold coated with ametallic coating or tagged with one or more metallic markers.

In some variations, where ferromagnetic or metallic-marked wires,stents, or scaffolds are used to support organs, lumens, or cavities ofa patient, the device 100 can be used to not only detect such wires,stents, or scaffolds (e.g., for possible removal or inspection) but alsoto detect or pinpoint the location of such organs, lumens, or cavitiesfor further procedures.

FIG. 12 illustrates that the metal detection device 100 can be used whenthe body cavity or body part of the patient is at least partiallycovered, shielded, or ensconced by a magnetic blanket 322 or magneticshield. In some variations, the magnetic blanket 322 can comprise aplurality of magnets embedded or otherwise disposed within layers of theblanket.

For example, the magnetic blanket 322 can be used to cover an abdomen ofthe patient when the device 100 is used to detect RSIs or retainedsharps within the abdomen of the patient.

The magnetic blanket 322 or shield can be used to create a controlledmagnetic environment. The magnetic blanket 322 or shield can also beused to enhance certain signals or magnetic field distortions generatedby certain RSIs (e.g., RFID-tagged sponges 302) once the distal sensingportion 136 of the device 100 is within the body cavity of the patientand the detection sensitivity of the device is adjusted such that themagnetic field distortion created by the magnetic blanket 322 or shieldis accounted for.

The magnetic blanket 322 or shield can be used to at least partiallycover, shield, or ensconce a body cavity or body part of the patientwhen the device 100 is used to undertake intracorporeal detection ofRSIs, implants, surgical tools, or a combination thereof within the bodycavity or body part. For example, the magnetic blanket 322 or shield canbe used to at least partially cover, shield, or ensconce a body cavityor body part of the patient when the device 100 is used to undertakeintracorporeal detection of needles, sponges 300, wires 312, stents 320or other scaffolds, ferromagnetic or metallically-marked catheters,sheaths, or other surgical equipment, or parts or combinations thereof.

Alternatively or additionally, the magnetic blanket 322 can be used towrap certain needles, wires, or other tools before surgery in order tomagnetize such needles, wires, or tools to make such needles, wires, ortools more easily detectable by the device 100.

FIG. 13 is a signal diagram illustrating the distal sensing portion 136of the device 100 passing over a surgical needle (e.g., a 5-0 13 mmsurgical needle). The device 100 can be operating in a high speed andhigh sensitivity mode in the scenario shown in FIG. 13 . In this mode,the sensitivity wheel(s) 115 can be dialed forward or distally such thatthe sensitivity level is above a starting default level (e.g., level 8,9, 10, or 11). In this mode, the one or more processors of themicrocontroller 185 can be programmed to execute instructions to applyone or more signal filters (e.g., a high-pass filter, a low-pass filter,or a combination thereof) to the differential signal to obtain thedetection signal. Moreover, each time step in FIG. 13 can representapproximately 1.5 milliseconds.

For example, the one or more processors of the microcontroller 185 canbe programmed to execute instructions to first calculate a differentialsignal from magnetic field measurements obtained from the first proximalmagnetometer 202, the second proximal magnetometer 204, the first distalmagnetometer 208, and the second distal magnetometer 210. Morespecifically, the one or more processors of the microcontroller 185 canbe programmed to execute instructions to calculate the differentialsignal using any of the equations 1-18 above. In the scenario shown inFIG. 13 , the differential signal is calculated using equation 2 (alsoreferred to as an on-axis global differential signal).

The one or more processors of the microcontroller 185 can be programmedto execute further instructions to apply a high-pass filter to thedifferential signal (e.g., the on-axis global differential signal). Thehigh-pass filter can get rid of low-frequency noise in the differentialsignal. For example, the high-pass filter can get rid of drift andoffset and bring the average signal back to zero.

The one or more processors of the microcontroller 185 can be programmedto execute additional instructions to apply a number of low-pass filtersto the high-pass filtered signal. For example, the one or moreprocessors of the microcontroller 185 can be programmed to executeadditional instructions to apply a second order low-pass filter (alsoknown as a two-pole filter) to get rid of high-frequency noise in thehigh-pass filtered signal. The low-pass filter or second order filter(or two-pole filter) can more aggressively cut off high frequency noise.In some variations, the high-pass filter can have a cutoff of 5.5 Hz andthe low-pass filter can have a cutoff of 10 Hz.

The one or more processors of the microcontroller 185 can be programmedto execute further instructions to take the absolute value of thelow-pass filtered signal and to apply a smoothing function(smoothPoints=10) to the low-pass filtered signal to obtain thedetection signal.

The one or more processors of the microcontroller 185 can be programmedto execute additional instructions to compare the detection signalagainst a sensitivity threshold or detection threshold. Moreover, theone or more processors of the microcontroller 185 can be programmed toexecute further instructions to instruct the output component (e.g., thespeaker and/or LED lights) to generate a user output (e.g., a beepingsound, a flashing light, a light of increasing intensity, or acombination thereof) when the detection signal exceeds the sensitivityor detection threshold.

As shown in FIG. 13 , the detection signal exceeds the detectionthreshold when the distal sensing portion 136 is passed over thesurgical needle. The inset in FIG. 13 also illustrates that signal noisebefore the detection is addressed by the filter steps which produces amore accurate detection signal that would not result in false positivedetection.

FIG. 13 also illustrates that the sensitivity level of the device 100can be decreased and the sensitivity or detection threshold can beautomatically increased when the magnetometers are periodically reset tofilter out any settling events or level changes.

FIG. 14 is a signal diagram illustrating an operator (e.g., a surgeon orother medical professional) adjusting the sensitivity level of thedevice 100 at the same time that the operator is also sliding the testrod slider 117 forward to test the functionality of the device using thetest rod 133. The device 100 can be operating in a low speed and lowsensitivity mode in the scenario shown in FIG. 14 (e.g., a sensitivitylevel of 7 or below). In this mode, the one or more processors of themicrocontroller 185 can be programmed to execute instructions to apply aderivative and apply a motion blocking algorithm to the differentialsignal to obtain the detection signal. The motion blocking algorithm ormotion blocker signal will be discussed in more detail in the followingsections (see, e.g., FIGS. 17A and 17B). Moreover, each time step inFIG. 14 can represent approximately 28 milliseconds.

FIG. 14 illustrates that the operator can raise the sensitivity level(i.e., lower the sensitivity threshold) by dialing the sensitivitywheel(s) 115 forward or distally. The operator can raise the sensitivitylevel (for example, from level 0 to level 4) to ensure that the test rod133 is sensed by the distal sensing portion 136.

Each spike in the detection signal can represent an instance where adistal segment of the test rod 133 is extended out of the spring tube137 and into the sensor housing 141 in proximity to the magnetometers.The larger spikes can be instances in which the test rod 133 is extendedfurther into the sensor housing 141 in close proximity to themagnetometers. The smaller spikes can be instances in which the distalsegment of the test rod 133 is extended only slightly into the sensorhousing 141 or being retracted back into the spring tube 137.

FIG. 15 is a signal diagram illustrating the distal sensing portion 136passing over part of a metal guidewire. For example, the guidewire canbe a straight fixed core guidewire made in part of stainless steel. Asshown in FIG. 15 , the detection signal can exceed a sensitivitythreshold or detection threshold when the distal sensing portion 136passes over part of the metal guidewire. In this example, the distalsensing portion 136 is within 10 mm of the metal guidewire when thedistal sensing portion 136 passes over the metal guidewire.

The output component (e.g., the speaker 181, the proximal LED 173, thedistal LED 183, or a combination thereof) can generate a user output(e.g., a beeping sound, a flashing light or a brighter light, or acombination thereof) to alert a user that the distal sensing portion 136has passed over the metal guidewire.

The device 100 can be operating in a low speed and low sensitivity modein the scenario shown in FIG. 15 . In this mode, the sensitivitywheel(s) 115 can be dialed backward or proximally such that thesensitivity level is below a starting default level (e.g., level 7 orbelow). Also, in this mode, the one or more processors of themicrocontroller 185 can be programmed to execute instructions to apply aderivative to the differential signal to obtain the detection signal.Moreover, each time step in FIG. 15 can represent approximately 28milliseconds.

FIG. 16A is a signal diagram illustrating the effects on the detectionsignal as the trigger is pulled. As shown in FIG. 16A, the trigger 105is squeezed twice in succession and then squeezed three additional timesin succession after a brief period where the trigger 105 is notactuated. Each time the trigger 105 is squeezed, a spike in the triggerpotentiometer signal is observed. As seen in FIG. 16A, the sensitivitywheel(s) 115 and the test rod slider 117 are not actuated during thisperiod as evidenced by the flat sensitivity wheel potentiometer signaland the test rod potentiometer signal, respectively.

The device 100 can be operating in a low speed and low sensitivity modein the scenario shown in FIG. 16A. In this mode, the sensitivitywheel(s) 115 can be dialed backward or proximally such that thesensitivity level is below a starting default level (e.g., level 7 orbelow). Also, in this mode, the one or more processors of themicrocontroller 185 can be programmed to execute instructions to apply aderivative to the differential signal to obtain the detection signal.Moreover, each time step in FIG. 16A can represent approximately 28milliseconds.

FIG. 16A shows that the detection signal jump or spikes each time thetrigger 105 is squeezed, even when no RSIs or other ferromagnetic sharpsare detected. The detection signal can jump or spike as a result of thedistal sensing portion 136 moving in response to the flexible portion145 bending or curling from the trigger pull.

FIG. 16B is a signal diagram illustrating the device 100 automaticallyraising the sensitivity threshold or detection threshold in response tothe trigger pulling scenario shown in FIG. 16A. For example, the one ormore processors of the microcontroller 185 can be programmed to executeinstructions to observe a motion signal from the accelerometer andgyroscope of the IMU 159 disposed in the distal sensing portion 136.When the motion signal exceeds a preset or predetermined motionthreshold, the one or more processors of the microcontroller 185 can beprogrammed to execute further instructions to automatically raise thesensitivity threshold or detection threshold such that the sensitivitylevel or detection sensitivity of the device 100 is lowered. As shown inFIG. 16B, the sensitivity or detection threshold is raised during thetwo instances (the two trigger pulls and the three trigger pulls) whenthe trigger 105 is pulled in succession.

FIG. 16C is another signal diagram illustrating the device 100automatically raising the sensitivity threshold or detection thresholdin response to the trigger pulling scenario shown in FIG. 16A. the oneor more processors of the microcontroller 185 can be programmed toexecute instructions to observe a trigger velocity signal from thetrigger potentiometer 171 indicative of a trigger speed. When thetrigger velocity signal exceeds a preset or predetermined velocitythreshold (e.g., when the trigger 105 is pulled too fast), the one ormore processors of the microcontroller 185 can be programmed to executefurther instructions to automatically raise the sensitivity threshold ordetection threshold such that the sensitivity level or detectionsensitivity of the device 100 is lowered. As shown in FIG. 16C, thesensitivity or detection threshold is raised during the two instanceswhen the trigger 105 is pulled in succession.

FIGS. 17A and 17B are signal diagrams illustrating a motion blocking orblocker signal used to scale down the detection signal in the event thedistal sensing portion 136 is subjected to sudden motions. The device100 can be operating in a low speed and low sensitivity mode in thescenarios shown in FIGS. 17A and 17B. In this mode, the sensitivitywheel(s) 115 can be dialed backward or proximally such that thesensitivity level is below a starting default level (e.g., level 7 orbelow). Also, in this mode, the one or more processors can be programmedto execute instructions to apply a derivative to the differential signalto obtain the detection signal. Moreover, each time step in FIGS. 17Aand 17B can represent approximately 28 milliseconds.

FIG. 17A illustrates a raw motion signal calculated from data receivedfrom the accelerometer and gyroscope of the IMU 159. The device 100 canuse the raw motion signal to calculate a motion blocker signal to scaledown the detection signal. For example, the one or more processors ofthe microcontroller 185 can be programmed to execute instructions tocalculate the motion blocker signal by comparing the raw motion signalagainst a motion threshold. For example, the motion blocker signal canbe 1 when the raw motion signal falls below the motion threshold.However, the motion blocker signal can be raised based on the size ofthe raw motion signal. The size of the motion blocker signal cansubstantially track the size of the raw motion signal when the rawmotion signal exceeds the motion threshold. The one or more processorsof the microcontroller 185 can be programmed to execute furtherinstructions to divide a detection signal by the motion blocker signalto obtain a more motion-resistant detection signal. FIG. 17A illustratesthe detection signal after undergoing motion blocking. An exampledetection threshold is also provided in FIG. 17A to illustrate how thedetection signal (with motion blocking) remains below the detectionthreshold, thereby preventing false positive detections.

FIG. 17B illustrates the detection signal without having undergone theaforementioned motion blocking steps. As shown in FIG. 17B, thedetection signal (without motion blocking) exceeds the same detectionthreshold shown in FIG. 17A on multiple occasions, thereby increasingthe likelihood of numerous false positive detections.

FIG. 18 illustrates a method 500 of detecting a magnetic object withinthe body of a patient. The method 500 comprises introducing a part ofthe metal detection device 100 into the body of the patient in step 502.The metal detection device 100 can comprise a handle 102, a shaft 131extending from the handle 102, and a microcontroller 185 comprising oneor more processors and memory units, an output component, and a distalsensing portion 136 positioned distally of the shaft 131. The distalsensing portion 136 can comprise a proximal gradiometer 200 comprising afirst proximal magnetometer 202 and a second proximal magnetometer 204and a distal gradiometer 206 comprising a first distal magnetometer 208and a second distal magnetometer 210.

The method 500 can also comprise calculating, using the one or moreprocessors, a differential signal from magnetic field measurementsobtained from the first proximal magnetometer 202, the second proximalmagnetometer 204, the first distal magnetometer 208, and the seconddistal magnetometer 210 in step 504.

The method 500 can also comprise applying, using the one or moreprocessors, at least one of a signal filter and a derivative to thedifferential signal calculated to obtain a detection signal in step 506.The method 500 can further comprise comparing, using the one or moreprocessors, the detection signal against a sensitivity threshold ordetection threshold in step 508. The method 500 can also comprisegenerating a user output, using the output component, when the detectionsignal exceeds the sensitivity or detection threshold in step 510. Thedetection signal can exceed the sensitivity or detection threshold whenthe distal sensing portion 136 passes by or passes over a ferromagneticRSI or another ferromagnetic object.

FIG. 19 illustrates another method 600 of detecting a magnetic objectwithin a body of a patient. The method 600 can comprise introducing apart of a metal detection device 100 (e.g., the distal segment of themetal detection device 100) into the body of the patient in step 602.The metal detection device 100 can comprise a handle 102, a shaft 131extending from the handle 102, a distal sensing portion 136 positioneddistally of the shaft 131, a flexible portion 145 connecting the shaft131 to the distal sensing portion 136, and a microcontroller 185comprising one or more processors and memory units, and an outputcomponent.

The distal sensing portion 136 can comprise a plurality ofmagnetometers. For example, the distal sensing portion 136 can comprisea proximal gradiometer 200 comprising a first proximal magnetometer 202and a second proximal magnetometer 204 and a distal gradiometer 206comprising a first distal magnetometer 208 and a second distalmagnetometer 210.

The method 600 can also comprise squeezing a trigger 105 on the handle102 to bend the flexible portion 145 when the distal sensing portion 136and at least part of the flexible portion 145 is within the body of thepatient in step 604. The method 600 can further comprise calculating,using the one or more processors, a detection signal from magnetic fieldmeasurements obtained from the plurality of magnetometers in step 606.Calculating the detection signal can further comprise calculating, usingthe one or more processors, a differential signal from magnetic fieldmeasurements obtained from the first proximal magnetometer, the secondproximal magnetometer, the first distal magnetometer, and the seconddistal magnetometer. Moreover, the method 600 can also comprise applyingat least one of a signal filter and a derivative to the differentialsignal calculated to obtain the detection signal.

The method 600 can further comprise comparing, using the one or moreprocessors, the detection signal against a sensitivity threshold ordetection threshold in step 608. The method 600 can also comprisegenerating a user output, using the output component, when the detectionsignal exceeds the sensitivity threshold or detection threshold in step610. The detection signal can exceed the sensitivity or detectionthreshold when the distal sensing portion 136 passes by or passes over aferromagnetic RSI or another ferromagnetic object.

The method 600 can also comprise determining a trigger speed based ondata obtained from a trigger potentiometer 171 within the handle 102.The trigger potentiometer 171 can be coupled to the trigger 105. Themethod 600 can further comprise adjusting, using the one or moreprocessors, the sensitivity or detection threshold based on the triggerspeed.

FIG. 20 illustrates a method 700 of testing a functionality of a metaldetection device 100. The method 700 can comprise providing a metaldetection device 100 in step 702. The metal detection device 100 cancomprise a handle 102, a shaft 131 extending from the handle 102, adistal sensing portion 136 positioned distally of the shaft 131, aflexible portion 145 connecting the shaft 131 to the distal sensingportion 136, and a microcontroller 185 comprising one or more processorsand memory units, and an output component.

The distal sensing portion 136 can comprise a plurality ofmagnetometers. For example, the distal sensing portion 136 can comprisea proximal gradiometer 200 comprising a first proximal magnetometer 202and a second proximal magnetometer 204 and a distal gradiometer 206comprising a first distal magnetometer 208 and a second distalmagnetometer 210.

The method 700 can also comprise sliding a test rod slider 117 on thehandle 102 in a distal direction toward the shaft 131. Sliding the testrod slider 117 causes a distal segment of a test rod 133 housed within alumen extending through the shaft 131 to be translated into the sensorhousing 141 in step 704.

The method 700 can also comprise calculating, using the one or moreprocessors, a detection signal from magnetic field measurements obtainedfrom the plurality of magnetometers when the distal segment of the testrod 133 is translated into the sensor housing 141 in step 706. Themethod 700 can further comprise comparing, using the one or moreprocessors, the detection signal against a sensitivity threshold ordetection threshold in step 708. The method 700 can also comprisegenerating a user output, using the output component, when the detectionsignal exceeds the sensitivity threshold in step 710.

This application also incorporates by reference U.S. Patent PublicationNo. US 2017/0347915 A1, published on Dec. 7, 2017.

Each of the individual variations or embodiments described andillustrated herein has discrete components and features which may bereadily separated from or combined with the features of any of the othervariations or embodiments. Modifications may be made to adapt aparticular situation, material, composition of matter, process, processact(s) or step(s) to the objective(s), spirit or scope of the presentinvention.

Methods recited herein may be carried out in any order of the recitedevents that is logically possible, as well as the recited order ofevents. Moreover, additional steps or operations may be provided orsteps or operations may be eliminated to achieve the desired result.

Furthermore, where a range of values is provided, every interveningvalue between the upper and lower limit of that range and any otherstated or intervening value in that stated range is encompassed withinthe invention. Also, any optional feature of the inventive variationsdescribed may be set forth and claimed independently, or in combinationwith any one or more of the features described herein. For example, adescription of a range from 1 to 5 should be considered to havedisclosed subranges such as from 1 to 3, from 1 to 4, from 2 to 4, from2 to 5, from 3 to 5, etc. as well as individual numbers within thatrange, for example 1.5, 2.5, etc. and any whole or partial incrementstherebetween.

All existing subject matter mentioned herein (e.g., publications,patents, patent applications) is incorporated by reference herein in itsentirety except insofar as the subject matter may conflict with that ofthe present invention (in which case what is present herein shallprevail). The referenced items are provided solely for their disclosureprior to the filing date of the present application. Nothing herein isto be construed as an admission that the present invention is notentitled to antedate such material by virtue of prior invention.

Reference to a singular item, includes the possibility that there areplural of the same items present. More specifically, as used herein andin the appended claims, the singular forms “a,” “an,” “said” and “the”include plural referents unless the context clearly dictates otherwise.It is further noted that the claims may be drafted to exclude anyoptional element. As such, this statement is intended to serve asantecedent basis for use of such exclusive terminology as “solely,”“only” and the like in connection with the recitation of claim elements,or use of a “negative” limitation. Unless defined otherwise, alltechnical and scientific terms used herein have the same meaning ascommonly understood by one of ordinary skill in the art to which thisinvention belongs.

In understanding the scope of the present disclosure, the term“comprising” and its derivatives, as used herein, are intended to beopen-ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member”“element,” or “component” when used in the singular can have the dualmeaning of a single part or a plurality of parts. As used herein, thefollowing directional terms “forward, rearward, above, downward,vertical, horizontal, below, transverse, laterally, and vertically” aswell as any other similar directional terms refer to those positions ofa device or piece of equipment or those directions of the device orpiece of equipment being translated or moved. Finally, terms of degreesuch as “substantially”, “about” and “approximately” as used herein meana reasonable amount of deviation (e.g., a deviation of up to ±0.1%, ±1%,±5%, or ±10%, as such variations are appropriate) from the specifiedvalue such that the end result is not significantly or materiallychanged.

This disclosure is not intended to be limited to the scope of theparticular forms set forth, but is intended to cover alternatives,modifications, and equivalents of the variations or embodimentsdescribed herein. Further, the scope of the disclosure fully encompassesother variations or embodiments that may become obvious to those skilledin the art in view of this disclosure.

We claim:
 1. A metal detection device, comprising: a handle; a shaftextending from the handle; a distal sensing portion positioned distallyof the shaft, wherein the distal sensing portion comprises: a proximalgradiometer comprising a first proximal magnetometer and a secondproximal magnetometer, a distal gradiometer comprising a first distalmagnetometer and a second distal magnetometer, wherein the firstproximal magnetometer, the second proximal magnetometer, the firstdistal magnetometer, and the second distal magnetometer are two-axismagnetometers, each having a +x-axis and a +y-axis, wherein the +x-axisof the first proximal magnetometer is oriented opposite the +x-axis ofthe second proximal magnetometer, wherein the +y-axis of the firstproximal magnetometer is oriented opposite the +y-axis of the secondproximal magnetometer, wherein the +x-axis of the first distalmagnetometer is oriented opposite the +x-axis of the second distalmagnetometer, and wherein the +y-axis of the first distal magnetometeris oriented opposite the +y-axis of the second distal magnetometer; anoutput component configured to generate a user output to alert a user ofa detected object; a microcontroller comprising one or more processorsand memory units, wherein the one or more processors are programmed toexecute instructions stored in the memory units to: calculate adifferential signal from magnetic field measurements obtained from thefirst proximal magnetometer, the second proximal magnetometer, the firstdistal magnetometer, and the second distal magnetometer; apply at leastone of a signal filter and a derivative to the differential signalcalculated to obtain a detection signal, where the signal filtercomprises at least one of a high-pass filter and a low-pass filter;compare the detection signal against a threshold; and instruct theoutput component to generate the user output when the detection signalexceeds the threshold.
 2. The metal detection device of claim 1, whereinthe distal sensing portion further comprises: a proximal rigid printedcircuit board (PCB), wherein the first proximal magnetometer and thesecond proximal magnetometer are coupled to the proximal rigid PCB; adistal rigid PCB, wherein the first distal magnetometer and the seconddistal magnetometer are coupled to the distal rigid PCB; and a distalflexible circuit disposed in between the proximal rigid PCB and thedistal rigid PCB and connecting the proximal rigid PCB to the distalrigid PCB, wherein the distal rigid PCB is angularly rotated withrespect to the proximal rigid PCB about the distal flexible circuit by atwist angle of about 45 degrees.
 3. The metal detection device of claim1, wherein the distal sensing portion is covered by a sensor housing,wherein the sensor housing has a housing diameter, wherein the housingdiameter is between about 3.0 mm to about 10.0 mm.
 4. The metaldetection device of claim 1, further comprising a flexible tubingcoupling the distal sensing portion to the shaft, wherein the flexibletubing is bendable and comprises a straightened configuration and a bentconfiguration, and wherein the distal sensing portion is positionedcloser to the shaft when the flexible tubing is in the bentconfiguration.
 5. The metal detection device of claim 4, wherein theflexible tubing is made in part of a thermoplastic elastomer.
 6. Themetal detection device of claim 4, wherein the flexible tubing is madein part of Pebax®.
 7. The metal detection device of claim 4, wherein thehandle further comprises a trigger configured to control bending of theflexible tubing, wherein the trigger is connected to the flexible tubingby a pull cable extending through the shaft and the flexible tubing,wherein squeezing the trigger pulls the pull cable to bend the flexibletubing toward the shaft.
 8. The metal detection device of claim 7,wherein the handle further comprises a trigger potentiometer coupled tothe trigger, wherein the one or more processors of the microcontrollerare programmed to execute instructions to determine a trigger speed ormotion based on data obtained from the trigger potentiometer.
 9. Themetal detection device of claim 1, wherein the shaft is rotatable withrespect to a longitudinal axis of the shaft.
 10. The metal detectiondevice of claim 1, wherein the handle further comprises a clocking ringcoupled to the shaft, wherein the shaft is rotatable in response to arotation of the clocking ring.
 11. The metal detection device of claim10, wherein the handle further comprises a locking ring, wherein thelocking ring comprises a plurality of locking splines configured toobstruct the clocking ring from rotating, wherein the clocking ring isconfigured to be pushed in a distal direction to free the clocking ringfrom the locking splines of the locking ring, and wherein the clockingring is rotatable after being pushed in the distal direction.
 12. Themetal detection device of claim 1, further comprising a test rodconfigured to translate into and retract out of a sensor housingcovering the distal sensing portion to verify a functionality of themetal detection device.
 13. The metal detection device of claim 12,wherein the test rod is partially housed within a spring tube, whereinthe spring tube extends through the shaft and a flexible tubing couplingthe shaft to the distal sensing portion, wherein the flexible tubing isbendable such that a tubing distal end bends toward the shaft when atrigger on the handle is squeezed, and wherein the spring tube isconfigured to bias the flexible tubing back to an unbent configurationwhen the trigger is released.
 14. The metal detection device of claim13, wherein the spring tube is made in part of polyethyleneterephthalate.
 15. The metal detection device of claim 12, wherein thehandle further comprises a test rod slider and wherein the test rodslider is configured to be actuated distally or proximally to translatethe test rod axially within the shaft.
 16. The metal detection device ofclaim 15, wherein the handle further comprises a slider potentiometercoupled via gears to part of the test rod slider, wherein the one ormore processors of the microcontroller are programmed to executeinstructions to: determine a slider position based on data obtained fromthe slider potentiometer, wherein the slider position is indicative of arelative positioning of the test rod with respect to at least one of thefirst proximal magnetometer, the second proximal magnetometer, the firstdistal magnetometer, and the second distal magnetometer; and instructthe output component to generate the same or another instance of theuser output when the test rod is positioned in proximity to at least oneof the first proximal magnetometer, the second proximal magnetometer,the first distal magnetometer, and the second distal magnetometer. 17.The metal detection device of claim 12, wherein the one or moreprocessors of the microcontroller are programmed to execute furtherinstructions to adjust the threshold when the test rod is positioned inproximity to at least one of the first proximal magnetometer, the secondproximal magnetometer, the first distal magnetometer, and the seconddistal magnetometer in order to test an operability of the metaldetection device.
 18. The metal detection device of claim 1, wherein thehandle comprises a sensitivity wheel, and wherein the one or moreprocessors of the microcontroller are programmed to execute furtherinstructions to adjust the threshold in response to a rotation of thesensitivity wheel.
 19. The metal detection device of claim 18, whereinthe handle further comprises a sensitivity rotary potentiometer coupledto the sensitivity wheel, wherein the one or more processors of themicrocontroller are programmed to execute instructions to determine awheel rotational direction based on data obtained from the sensitivityrotary potentiometer.
 20. The metal detection device of claim 19,wherein the one or more processors of the microcontroller are programmedto execute further instructions to apply either the signal filter or thederivative to the differential signal calculated based on the wheelrotational direction.